Printed board and method for manufacturing mounted article

Abstract

A printed circuit board (10) for mounting a heat dissipation member (12) is provided with a first pad (16), a second pad (18) connected to a part of the peripheral edge of the first pad (16), and a solder paste (20) applied to the second pad (18). The solder paste (20) has a protruding portion (22) that protrudes from the second pad (18) toward the first pad (16) via a connection portion between the first pad (16) and the second pad (18). The protruding portion (22) extends to the inside of the terminal arrangement region (16AR) of the first pad (16).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a printed circuit board and a mounted product. Background Art

[0002] Sometimes, electronic components that require relatively large driving power are mounted on a printed circuit board. In this case, in order to suppress the heat generated by the power consumption of the electronic components, a heat dissipation component is sometimes mounted on the printed circuit board. When a heat dissipation component is mounted on a printed circuit board, solder is generally used.

[0003] Japanese Patent Publication No. 2014-212276 discloses a printed circuit board in which solder paste is divided into a plurality of partitions and applied to pads. The solder paste is divided into a plurality of partitions by a grid-shaped solder resist dam provided on the pads of the printed circuit board. The solder resist dam acts as a discharge channel for voids generated in the molten solder paste, i.e., the molten solder. Therefore, the voids generated in the molten solder are reduced. Summary of the invention

[0004] However, if the solder paste is divided into a plurality of partitions, the mounting area of ​​the heat dissipation component mounted on the printed circuit board becomes smaller than when the solder paste is not divided, and the heat dissipation performance is reduced. Therefore, as a problem, suppressing the voids without reducing the heat dissipation performance is listed.

[0005] The object of the present invention is to solve the above-mentioned problems.

[0006] A first aspect of the present invention is a printed circuit board used for installing a heat dissipation component, wherein the printed circuit board comprises: a first solder pad used for installing the heat dissipation component; a second solder pad arranged around the first solder pad and connected to a portion of the periphery of the first solder pad; and a solder paste applied on the second solder pad, the solder paste having a protrusion protruding from the second solder pad to the first solder pad via a connecting portion between the first solder pad and the second solder pad, the protrusion extending to an area where terminals of the heat dissipation component are arranged, i.e., the inner side of a terminal arrangement area of ​​the first solder pad.

[0007] A second embodiment of the present invention is a method for manufacturing an installation product, wherein a heat dissipation component is installed on a printed circuit board, and the method for manufacturing the installation product includes a melting process for melting solder paste applied to the printed circuit board, wherein the printed circuit board comprises: a first solder pad; a second solder pad connected to a portion of a periphery of the first solder pad; and the solder paste applied on the second solder pad, wherein the solder paste has a protrusion protruding toward the first solder pad via a connecting portion between the first solder pad and the second solder pad, wherein the protrusion extends to the inner side of an area where terminals of the heat dissipation component are arranged, i.e., an area where terminals of the first solder pad are arranged. In the melting process, the molten solder is moved from the second solder pad to the terminal arrangement area via the protrusion by the wetting force of the molten solder paste, i.e., the molten solder.

[0008] According to the aspect of the present invention, the voids can be suppressed without reducing the heat dissipation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a top view showing a printed circuit board according to the embodiment.

[0010] Figure 2 yes Figure 1 Cross-sectional view taken along arrow II-II.

[0011] Figure 3 This is a flowchart showing a method for manufacturing a mounted product.

[0012] Figure 4 It is a top view showing the flow of molten solder.

[0013] Figure 5 yes Figure 4 VV-direction sectional view.

[0014] Figure 6 It is a top view showing a printed circuit board according to Modification 1.

[0015] Figure 7 It is a top view showing a printed circuit board according to Modification 2.

[0016] Figure 8 It is a top view showing a printed circuit board according to Modification 3. DETAILED DESCRIPTION

[0017] [Implementation Method]

[0018] Figure 1 It is a top view showing the printed circuit board 10 according to the embodiment. Figure 2 yes Figure 1 The printed circuit board 10 is a printed wiring board without the heat dissipation component 12 installed. The printed circuit board 10 is used for the heat dissipation component 12 ( Figure 2The printed circuit board 10 includes a substrate 14, a first solder pad 16, a second solder pad 18 and a solder paste 20.

[0019] The first pad 16 is a metal foil for mounting the heat sink 12. The first pad 16 has a terminal configuration area 16AR. The terminal configuration area 16AR is an area where the terminal 12TL of the heat sink 12 is configured. The terminal 12TL is a soldered portion and is configured on the bottom surface of the heat sink 12. The terminal configuration area 16AR may be the same size as the terminal 12TL or larger than the terminal 12TL of the heat sink 12. Figure 1 and Figure 2 , an example is shown in which the terminal configuration area 16AR is larger than the terminal 12TL of the heat dissipation component 12. Figure 1 and Figure 2 In this case, the area of ​​the first pad 16 is approximately the same as the bottom surface of the heat dissipation component 12 .

[0020] The second pad 18 is a metal foil for applying the solder paste 20. No electronic components including the heat dissipation component 12 are mounted on the second pad 18. The second pad 18 is connected to a portion of the periphery of the first pad 16. In the present embodiment, the second pad 18 is connected to one side of the rectangular first pad 16. The side of the first pad 16 to which the second pad 18 is connected may also be one long side of the rectangular first pad 16. In addition, in the present embodiment, the second pad 18 is a rod-shaped extending in one direction, and the second pad 18 is arranged along the periphery of the printed substrate 10 (substrate 14).

[0021] The solder paste 20 is applied on the second pad 18. The solder paste 20 contains flux. The solder paste 20 is sometimes also called cream solder.

[0022] In the present embodiment, there are a plurality of solder pastes 20. Some of the plurality of solder pastes 20 have protrusions 22. The solder paste 20 having the protrusions 22 is sometimes referred to as a first solder paste 20_1. The first solder paste 20_1 is disposed near the connection portion between the first pad 16 and the second pad 18. The first solder paste 20_1 is larger than the size of the solder paste 20 without the protrusions 22. The solder paste 20 without the protrusions 22 is sometimes referred to as a second solder paste 20_2.

[0023] The protrusion 22 protrudes from the second pad 18 toward the first pad 16 via the connection portion between the first pad 16 and the second pad 18. The protrusion 22 extends to the inside of the terminal arrangement region 16AR of the first pad 16.

[0024] Figure 31 is a flowchart showing a method for manufacturing a mounted product. The mounted product is a printed circuit board 10 on which at least a heat dissipating component 12 is mounted. The method for manufacturing a mounted product includes a coating step P1, a placement step P2, a melting step P3, and a cooling step P4.

[0025] The coating step P1 is a step of coating the solder paste 20 on the second pads 18. In the coating step P1, for example, a solder printer is used. The solder printer uses a squeegee to coat the cream solder supplied onto the metal mask as the solder paste 20 onto the second pads 18 through the holes of the metal mask.

[0026] The arrangement step P2 is a step of arranging the terminal 12TL of the heat dissipation component 12 on the terminal arrangement region 16AR of the first pad 16. In this case, at least a portion of the protrusion 22 is arranged between the terminal 12TL of the heat dissipation component 12 and the terminal arrangement region 16AR of the first pad 16. The surface of the protrusion 22 facing the terminal arrangement region 16AR is in contact with the first pad 16. At least a portion of the surface of the protrusion 22 facing the terminal 12TL is in contact with the terminal 12TL.

[0027] The melting step P3 is a step of melting the solder paste 20 applied to the second pad 18. In the melting step P3, for example, a reflow soldering device is used. The reflow soldering device heats the solder paste 20 to a predetermined temperature. When the solder paste 20 is heated to the predetermined temperature, it melts. The melted solder paste 20 (molten solder) wets and flows (refer to Figure 4 , Figure 5 ). In this case, the first molten solder of the molten first solder paste 20_1 flows into the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12 starting from the protrusion 22 arranged between the terminal arrangement area 16AR of the first pad 16 and the terminal 12TL of the heat dissipation component 12. On the other hand, the second molten solder of the molten second solder paste 20_2 fuses with the first molten solder by wetting and spreading, and flows into the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12. In the case where voids are generated in the molten solder, the voids cannot follow the flow of the molten solder and come out of the molten solder.

[0028] Thus, in the melting step P3, the molten solder is moved from the second pad 18 to the terminal arrangement region 16AR of the first pad 16 via the protrusion 22 by the wetting force of the molten solder. Thus, even if the area of ​​the terminal arrangement region 16AR is large, the molten solder in an undivided state can be arranged in the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12. In addition, the void in the molten solder arranged in the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12 can be reduced.

[0029] The cooling step P4 is a step of cooling the molten solder disposed in the gap between the first solder pad 16 and the terminal 12TL of the heat dissipation component 12. In the cooling step P4, for example, a reflow soldering device is used. The reflow soldering device cools the molten solder to a predetermined cooling temperature. By cooling, the molten solder solidifies and becomes solidified solder.

[0030] [Modifications]

[0031] The above-mentioned embodiment may also be modified as follows. Hereinafter, descriptions overlapping with the above-mentioned embodiment will be appropriately omitted. In addition, in the following description, the same reference numerals are used for the same elements as those described in the above-mentioned embodiment.

[0032] (Variant 1)

[0033] Figure 6 1 is a plan view showing a printed circuit board 10 according to Modification 1. In the printed circuit board 10 according to this modification, the shape of the second pad 18 is different from that in the above-described embodiment.

[0034] In the case of this modified example, the second pad 18 includes a central portion 18PT1 and two L-shaped portions 18PT2. The central portion 18PT1 is connected to one long side of the rectangular first pad 16. The two L-shaped portions 18PT2 are arranged line-symmetrically with respect to an imaginary line passing through the center of the central portion 18PT1. Each L-shaped portion 18PT2 has a gap GP between the portion extending along the short side of the rectangular first pad 16 and the first pad 16.

[0035] In the case of this modification, the first solder paste 20_1 is disposed on the central portion 18PT1 of the second pad 18 , and the second solder paste 20_2 is disposed on either of the two L-shaped portions 18PT2 of the second pad 18 .

[0036] In the case of this modification, in the melting step P3, the first molten solder of the first solder paste 20_1 flows into the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12 from the protrusion 22 as a starting point. The second molten solder of the second solder paste 20_2 melts and fuses with the first molten solder by wetting and spreading, and flows into the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12 from the L-shaped portion 18PT2 via the central portion 18PT1.

[0037] Thus, also in this modification, in the melting step P3, the molten solder moves from the second pad 18 to the terminal arrangement region 16AR of the first pad 16 via the protrusion 22 due to the wettability of the molten solder. Therefore, in this modification, the same effects as those of the embodiment can be obtained.

[0038] (Variant 2)

[0039] Figure 7 1 is a plan view showing a printed circuit board 10 according to Modification 2. In the printed circuit board 10 according to this modification, the shape of the second pad 18 is different from that in the above-described embodiment.

[0040] In the case of this modified example, the second pad 18 is formed in a "T" shape. The second pad 18 includes a base portion 18PT3 and a protruding end portion 18PT4. The base portion 18PT3 is a portion extending along the long side of the rectangular first pad 16, and is connected to one long side of the first pad 16. The protruding end portion 18PT4 protrudes from a portion of the base portion 18PT3 on the opposite side of the connection portion of the base portion 18PT3 connected to the first pad 16.

[0041] In the case of this modification, the first solder paste 20_1 is arranged on the base portion 18PT3. The second solder paste 20_2 is arranged on the protrusion end portion 18PT4 and both ends of the base portion 18PT3. The second solder paste 20_2 is arranged so as to surround the first solder paste 20_1.

[0042] In the case of this modification, in the melting step P3, the first molten solder of the first solder paste 20_1 flows into the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12 from the protrusion 22 as a starting point. The second molten solder of the second solder paste 20_2 melts and fuses with the first molten solder by wetting and spreading, and flows into the gap between the first pad 16 and the terminal 12TL of the heat dissipation component 12 from both ends of the protrusion end 18PT4 and the base 18PT3.

[0043] Thus, also in this modification, in the melting step P3, the molten solder moves from the second pad 18 to the terminal arrangement region 16AR of the first pad 16 via the protrusion 22 due to the wettability of the molten solder. Therefore, in this modification, the same effects as those of the embodiment can be obtained.

[0044] (Variant 3)

[0045] Figure 8 1 is a plan view showing a printed circuit board 10 according to Modification 3. In the printed circuit board 10 according to this modification, the size and shape of the solder paste 20 are different from those in the above-described embodiment.

[0046] In the case of this modification, there is one solder paste 20. It is preferable that the application area of ​​the one solder paste 20 is the same as or close to the area of ​​the terminal arrangement region 16AR of the first pad 16.

[0047] When there are a plurality of solder pastes 20 as in the embodiment, Modification 1, or Modification 2, the total application area of ​​the plurality of solder pastes 20 is preferably the same as or close to the area of ​​the terminal arrangement region 16AR of the first pad 16 .

[0048] The invention that can be grasped from the above-mentioned embodiment and modified examples will be described below.

[0049] (1) The present invention is a printed circuit board 10 for mounting a heat dissipation component 12, comprising: a first solder pad 16 for mounting the heat dissipation component; a second solder pad 18 arranged around the first solder pad and connected to a portion of the periphery of the first solder pad; and a solder paste 20 applied to the second solder pad, the solder paste having a protrusion 22 protruding from the second solder pad to the first solder pad via a connecting portion between the first solder pad and the second solder pad, the protrusion extending to the inner side of an area where the terminal 12TL of the heat dissipation component is arranged, i.e., a terminal arrangement area 16AR of the first solder pad.

[0050] In the printed circuit board of the present invention, the molten solder can be moved from the second pad to the terminal configuration area of ​​the first pad with the protruding portion as the starting point by the wetting force of the molten solder as the molten solder paste. In addition, in the case where a void is generated in the molten solder, the void cannot follow the movement of the molten solder and come out of the molten solder. Therefore, even if the area of ​​the terminal configuration area is large, the molten solder can be arranged between the terminal configuration area and the terminal of the heat dissipation component in a non-divided state and in a state where the void is reduced. In this way, according to the printed circuit board of the present invention, the void can be suppressed without reducing the heat dissipation performance.

[0051] (2) In the present invention, in the printed circuit board, a part of the second pad may be arranged along the peripheral edge of the printed circuit board. Thus, the second pad can be arranged while ensuring the wiring pattern.

[0052] (3) In the present invention, in the printed circuit board, the second pad may be in the shape of a rod extending in one direction. Thus, the second pad can be arranged along the periphery of the printed circuit board. As a result, it is easy to arrange the second pad while ensuring the wiring pattern.

[0053] (4) In the present invention, in the printed circuit board, the second pad may include an L-shaped portion. This allows the second pad to be disposed at a corner of the printed circuit board. As a result, it is easy to dispose the second pad while ensuring a wiring pattern.

[0054] (5) The present invention is a method for manufacturing an installed product, wherein a heat dissipation component is installed on a printed circuit board, wherein the method for manufacturing the installed product includes a melting step P3 of melting solder paste applied to the printed circuit board, wherein the printed circuit board comprises: a first solder pad; a second solder pad connected to a portion of a periphery of the first solder pad; and the solder paste applied to the second solder pad, the solder paste having a protrusion protruding toward the first solder pad via a connecting portion between the first solder pad and the second solder pad, the protrusion extending to the inner side of an area where terminals of the heat dissipation component are arranged, i.e., a terminal arrangement area of ​​the first solder pad, wherein in the melting step, the molten solder is moved from the second solder pad to the terminal arrangement area via the protrusion due to the wetting force of the molten solder paste, i.e., molten solder.

[0055] Thus, even if the area of ​​the terminal arrangement region is large, the molten solder can be arranged in an undivided state between the terminal arrangement region and the terminal of the heat dissipation component. In addition, the voids generated in the molten solder can be made to come out of the molten solder without following the movement of the molten solder. Thus, according to the manufacturing method of the mounted product of the present invention, the voids can be suppressed without reducing the heat dissipation performance.

[0056] (6) The present invention may also be that in the manufacturing method of the mounted product, before the melting step, a configuration step P2 of configuring the terminal of the heat dissipation component on the terminal configuration area is further included, and the surface of the protrusion facing the terminal of the heat dissipation component contacts the terminal of the heat dissipation component. As a result, due to the surface tension of the molten solder, the molten solder easily moves in the gap between the terminal of the heat dissipation component and the first pad. Therefore, the movement efficiency of the molten solder between the terminal of the heat dissipation component and the first pad can be improved.

[0057] Explanation of symbols

[0058] 10—printed substrate, 12—heat dissipation component, 12TL—terminal, 14—substrate, 16—first solder pad, 16AR—terminal configuration area, 18—second solder pad, 20—solder paste, 20_1—first solder paste, 20_2—second solder paste, 22—protrusion.

Claims

1. A printed circuit board (10) for mounting a heat dissipation component (12), wherein the printed circuit board (10) is characterized in that it has: A first solder pad (16) for mounting the heat dissipation component; a second pad (18) disposed around the first pad and connected to a portion of the periphery of the first pad; and Solder paste (20) coated on the second pad, The solder paste has a protrusion (22) protruding from the second pad to the first pad via a connection portion between the first pad and the second pad. The protruding portion extends to the inner side of a terminal arrangement region (16AR) of the first pad, which is a region where the terminals (12TL) of the heat dissipating member are arranged.

2. The printed circuit board according to claim 1, characterized in that A portion of the second pad is arranged along a peripheral edge of the printed circuit board.

3. The printed circuit board according to claim 1 or 2, characterized in that: The second pad is in the shape of a rod extending in one direction.

4. The printed circuit board according to claim 1 or 2, characterized in that: The second pad includes an L-shaped portion.

5. A method for manufacturing a mounted product, wherein a heat dissipation component is mounted on a printed circuit board, the method for manufacturing the mounted product being characterized by: The method comprises a melting step (P3) of melting the solder paste applied to the printed circuit board. The printed circuit board comprises: a first solder pad; a second solder pad connected to a portion of the periphery of the first solder pad; and the solder paste applied on the second solder pad, the solder paste having a protrusion protruding toward the first solder pad via a connecting portion between the first solder pad and the second solder pad, the protrusion extending to an area where the terminals of the heat dissipation component are arranged, i.e., an inner side of a terminal arrangement area of ​​the first solder pad, In the melting step, the molten solder, which is the melted solder paste, is moved from the second pad to the terminal arrangement region via the protruding portion by the wetting force of the molten solder.

6. The method for manufacturing a mounted product according to claim 5, wherein: Prior to the melting step, the method further includes a step (P2) of arranging the terminals of the heat dissipation component on the terminal arrangement area. The surface of the protrusion facing the terminal of the heat dissipation member is in contact with the terminal of the heat dissipation member.

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