Circuit board and method for manufacturing mounting board

Abstract

This circuit board comprises: a substrate having a main surface; a first terminal and a second terminal provided on the main surface of the substrate; and one or more insulating material walls provided on the main surface of the substrate. The first and second terminals are disposed in a cavity surrounded by the wall(s), and at least one corner part formed by two wall frame parts of the wall(s) has a groove part penetrating from the inner peripheral surface to the outer peripheral surface.

Description

Circuit board and method for manufacturing mounting board

[0001] The present disclosure relates to a circuit board and a method for manufacturing a mounting board.

[0002] In recent years, advances in electronics have led to the development of technologies for mounting electronic components on substrates. For example, technologies have been developed for mounting a large number of bare chips of semiconductor light-emitting elements, such as light-emitting diodes (hereinafter referred to as "LEDs") used in lighting, display devices, and the like, on wiring substrates. For example, Patent Document 1 discloses an invention in which semiconductor light-emitting elements are inserted and bonded into a cavity that allows for easy positioning and arrangement of multiple semiconductor light-emitting elements. Furthermore, Patent Document 2 also discloses a technology for preventing semiconductor light-emitting elements from being carried away or solder bridges from forming when mounting electronic components using a paste-like bonding material.

[0003] JP 2006-93523 A JP 2004-47772 A

[0004] In some circuit boards, terminals and bonding materials are disposed inside walls made of insulating material. Electronic components are sometimes mounted on such circuit boards by filling the interior of the walls with components, mounting electronic components using a holding member, and then using a pressure reflow machine to press the electronic components into the walls, heat them, and bond them to the circuit board. In this case, excess components may remain inside the walls and on the upper part of the walls around the electronic components, preventing the electronic components from being sufficiently pressed in during the pressure reflow machine pressurization process, potentially resulting in poor connections between the bonding materials on the circuit board and the electronic components. There is also a need for improved positional accuracy of mounted electronic components on the circuit board.

[0005] An object of the present disclosure is to provide a circuit board that can suppress poor connections between the circuit board and electronic components and can improve the positional accuracy of mounted electronic components, and a method for manufacturing such a circuit board.

[0006] The circuit board according to the present disclosure is a circuit board comprising a substrate having a main surface, a first terminal and a second terminal provided on the main surface of the substrate, and one or more walls made of insulating material provided on the main surface of the substrate, wherein the first and second terminals are disposed within a cavity surrounded by the walls, and at least one of the corners formed by two wall frame portions of the walls has a groove portion that penetrates from the inner peripheral surface to the outer peripheral surface.

[0007] The method for manufacturing a mounted substrate according to the present disclosure is a method for manufacturing a mounted substrate by mounting electronic components on the above-mentioned circuit board, in which components are arranged on a base material, the electronic components are arranged, and then the electronic components are joined to terminals using a pressure reflow device.

[0008] According to the present disclosure, it is possible to provide a circuit board that can suppress poor connections between the circuit board and electronic components and improve the positional accuracy of mounted electronic components, and a method for manufacturing a mounted board.

[0009] FIG. 1 is a schematic cross-sectional view showing a mounting substrate including an example of a circuit board according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing an example of a circuit board according to an embodiment of the present disclosure. FIG. 3 is a plan view of the circuit board. FIGS. 4(a) and 4(b) are plan views of a circuit board according to a modified example. FIGS. 5(a), 5(b), and 5(c) are views of a wall frame portion of a wall as viewed from the thickness direction. FIGS. 6(a) and 6(b) are views showing an example of a rounded groove portion. FIGS. 7(a), 7(b), and 7(c) are plan views showing modified examples of the groove portion. FIG. 8 is a diagram illustrating the area of ​​the groove portion. FIGS. 9(a) and 9(b) are diagrams illustrating the width and length of the groove portion. FIGS. 10(a) and 10(b) are cross-sectional views showing a structure near a recessed portion. FIGS. 11(a), 11(b), and 11(c) are schematic views showing an example of a method for manufacturing a circuit board and a mounting substrate. FIG. 12 is a schematic view showing an example of a method for manufacturing a circuit board and a mounting substrate. FIGS. 13(a), 13(b), 13(c), 13(d), 13(e), and 13(f) are schematic views showing an example of a method for manufacturing a wall portion. Fig. 14 is a schematic cross-sectional view showing a circuit board according to a comparative example, and Figs. 15(a) and 15(b) are plan views illustrating recesses.

[0010] A circuit board 3 according to an embodiment of the present disclosure will be described with reference to Figures 1 to 3. Figure 1 is a schematic cross-sectional view showing a mounting substrate 1 including a circuit board 3 according to an embodiment of the present disclosure. Figure 2 is a schematic cross-sectional view showing the circuit board 3 according to an embodiment of the present disclosure. Figure 3 is a plan view of the circuit board 3.

[0011] 1, the mounting substrate 1 includes an electronic component 2 and a circuit board 3. The mounting substrate 1 is configured by mounting the electronic component 2 on the circuit board 3 via a bonding material 4.

[0012] The electronic component 2 includes a main body 6 and a pair of terminals 7. The main body 6 is a member for fulfilling the function of the electronic component 2. The terminals 7 are metal portions formed on the main surface of the main body 6. The terminals 7 may be made of a metal such as Cu, Ti, Au, Ni, Sn, Bi, P, B, In, Ag, Zn, Pd, Mo, Pt, or Cr, or an alloy selected from at least two of these metals. The electronic component 2 may be formed, for example, of a micro LED. The micro LED is a component that emits light in response to input from the circuit board 3.

[0013] The circuit board 3 includes a substrate 8, a wall 9, and a pair of terminals 10 (a first terminal and a second terminal). The substrate 8 is a flat body of the circuit board 3. The substrate 8 has a main surface 8a. The substrate 8 may be a printed circuit board for mounting the conductor patterns and electronic components of the circuit board 3 on the main surface 8a. A known resin material or ceramic material used for printed circuit boards may be used as the material for the substrate 8. Note that the following description may be given using XYZ coordinates set for the circuit board 3. The X-axis direction (second direction) is a direction parallel to the main surface 8a of the substrate 8, the Y-axis direction (third direction) is a direction parallel to the main surface 8a of the substrate 8 and perpendicular to the X-axis direction, and the Z-axis direction (first direction, height direction) is a direction perpendicular to the main surface 8a of the substrate 8.

[0014] The insulating wall 9 is provided on the main surface 8a of the substrate 8. The wall 9 is a member formed of an insulating material. The wall 9 protrudes from the substrate 8 toward the positive side in the Z-axis direction. As shown in FIG. 3 , in this embodiment, the wall 9 has wall frame portions 13A, 13B, 13C, and 13D provided on all four sides. The wall frame portions 13A and 13B face each other while being spaced apart in the X-axis direction and extend parallel to the Y-axis direction. The wall frame portion 13A is disposed on the positive side of the X-axis direction, and the wall frame portion 13B is disposed on the negative side. The wall frame portions 13C and 13D face each other while being spaced apart in the Y-axis direction and extend parallel to the X-axis direction. The wall frame portion 13C is disposed on the positive side of the Y-axis direction, and the wall frame portion 13D is disposed on the negative side. The wall frame portion 13A connects the positive ends of the wall frame portions 13C and 13D in the X-axis direction. The wall frame portion 13B connects the negative ends of the wall frame portions 13C and 13D in the X-axis direction. This results in the wall 9 having a rectangular frame-like structure when viewed in the height direction. The wall frame portions 13A and 13B form the short sides, and the wall frame portions 13C and 13D form the long sides. While the dimensions are not particularly limited, the dimension of the wall frame portions 13A and 13B in the Y-axis direction may be set to 10 μm to 60 μm. The dimension of the wall frame portions 13C and 13D in the X-axis direction may be set to 15 μm to 70 μm. The dimension of the short side of the inner peripheral surface of the interior of the wall 9 may be set to 8 μm or more and 44 μm or less. The dimension of the long side of the inner peripheral surface of the interior of the wall 9 may be set to 15 μm or more and 68 μm or less. The dimension of the short side of the inner peripheral surface of the wall 9 is the dimension in the Y-axis direction between the inner peripheral surface 13a of the wall frame portion 13C and the inner peripheral surface 13a of the wall frame portion 13D. The dimension of the long side of the inner peripheral surface of the wall 9 is the dimension in the X-axis direction between the inner peripheral surface 13a of the wall frame portion 13A and the inner peripheral surface 13a of the wall frame portion 13B. The wall 9 is made of a resin material such as epoxy resin, acrylic resin, phenolic resin, melamine resin, urea resin, or alkyd resin. Epoxy resin or acrylic resin is particularly preferred as the material for the wall 9.

[0015] 1 to 3, the terminal 10 is a metal portion provided on the main surface 8a of the substrate 8. The material of the terminal 10 may be Ni, Cu, Ti, Cr, Al, Mo, Pt, Au, or an alloy selected from at least two of these metals. A conductive film 12 is formed on the upper surface of the terminal 10. The material of the conductive film 12 may be a film of Ti, Cu, Ni, Al, Mo, Cr, Ag, or the like, or a film of a mixture of metal particles and a binder.

[0016] The bonding material 4 is a member that bonds the terminal 7 of the electronic component 2 to the terminal 10 of the circuit board 3. The bonding material 4 is formed by thermally bonding and integrating the bonding material 4A on the circuit board 3 side and the bonding material 4B on the electronic component 2 side (see FIG. 12 ). The bonding material 4 may contain Sn or may be composed of an alloy containing Sn. However, the bonding material 4 is not necessarily limited to Sn. The bonding material 4 may be composed of an alloy containing, in addition to Sn, an element that lowers the melting point of Sn. Examples of elements that lower the melting point of Sn include Bi. The bonding material 4 functions as solder. As a result, the terminal 10, the conductive film 12, the bonding material 4, and the terminal 7 are stacked between the substrate 8 and the main body 6 in this order from the top surface of the substrate 8. Note that the solder bonding is performed after the terminal 10, the conductive film 12, the bonding material 4, and the terminal 7 are stacked. Therefore, after soldering, a structure is formed in which the metals of the terminal 10, the conductive film 12, the bonding material 4, and the terminal 7 are melted and diffused. Such a structure after soldering may include a brittle intermetallic compound (IMC). If an intermetallic compound, which has a brittle structure, is present, it is prone to fracture due to external stress, and reliability is likely to decrease. Therefore, surrounding the electronic component 2 with the wall 9 has the effect of protecting the electronic component 2.

[0017] A cavity 11 is formed in the wall 9. The cavity 11 is formed by a through-hole that penetrates the wall 9 in the height direction. As a result, the top surface of the substrate 8 is exposed at the bottom side of the cavity 11. The cavity 11 is rectangular when viewed in the height direction (see FIG. 3 ). The terminals 7, 10, conductive film 12, and bonding material 4 are disposed in the cavity 11 surrounded by the wall 9, and are thereby surrounded by the wall 9 on all sides. Small gaps are formed between the terminals 7, 10, conductive film 12, and bonding material 4 and inner surfaces 13 a of the four wall frame portions 13A, 13B, 13C, and 13D that constitute the cavity 11.

[0018] Within the cavity 11, a component 20 is disposed between the electronic component 2 and bonding material 4 and the wall 9. This supports the electronic component 2 with the component 20, making it less likely to peel off from the circuit board 3. Furthermore, the force applied to the electronic component 2, bonding material 4, and terminals 7 and 10 is alleviated, improving reliability. Examples of materials used for the component 20 include epoxy resin, acrylic resin, phenolic resin, melamine resin, urea resin, alkyd resin, and mixtures thereof, as well as mixtures of the above resin materials with SiOx, ceramics, and the like. Epoxy resin and acrylic resin are particularly preferred. The viscosity of the component 20 during filling is preferably 1 Pa to 20 Pa, and more preferably 5 Pa to 10 Pa.

[0019] As shown in FIG. 2 , the circuit board 3 has a configuration in which the electronic component 2 and the constituent material 20 have been removed from the mounting board 1 shown in FIG. 1 . In the circuit board 3, a bonding material 4A containing a metal element is disposed above the terminal 10 (on the upper surface of the conductive film 12). The circuit board 3 includes a bonding material 4A (first bonding material) disposed on the X-axis direction side of the terminal 10A, and a bonding material 4A (second bonding material) disposed on the negative side of the X-axis direction of the terminal 10B. As described above, these bonding materials 4A constitute part of the bonding material 4 in a stage prior to thermally bonding the electronic component 2 and the mounting board 1. In the state of the circuit board 3, the pair of terminals 10, the conductive film 12, and the bonding material 4A are disposed within a wall 9 formed by an insulator.

[0020] As shown in Figure 3, the rectangular frame-shaped wall 9 has wall frame portions 13A, 13B, 13C, and 13D provided on all four sides, resulting in four corners 14A, 14B, 14C, and 14D. Corner portion 14A is formed by wall frame portions 13A and 13C. Corner portion 14B is formed by wall frame portions 13B and 13C. Corner portion 14C is formed by wall frame portions 13A and 13D. Corner portion 14D is formed by wall frame portions 13B and 13D. At least one of corners 14A, 14B, 14C, and 14D has at least one groove portion 30 that penetrates from the inner circumferential surface 13a to the outer circumferential surface 13b.

[0021] A rectangular reference shape T1 is set to have the smallest area circumscribing the inner circumferential surface 13a of the cavity 11 of the wall 9 when viewed from the height direction (first direction). A rectangular reference shape T2 is set to have the largest area inscribing the outer circumferential surface 13b of the wall 9 when viewed from the height direction. In this embodiment, the reference shapes T1 and T2 are rectangular. These reference shapes T1 and T2 are set imaginarily and are shown by imaginary lines in FIG. 3 . A line connecting the corners of the imaginary reference shapes T1 and T2 is defined as a reference line SL. In this embodiment, the groove portion 30 may extend along the direction in which the reference line SL extends. The groove portion 30 extends along an extension direction LD. In this embodiment, the extension direction of the reference line SL and the extension direction LD are parallel to each other, but they do not have to be parallel to each other. The definition of the extension direction LD will be described later. For example, in the example shown in FIG. 3 , the groove portion 30 includes both the corners of the reference shape T1 and the corners of the reference shape T2. However, the groove portion 30 may have a shape that does not include the corners of the reference shape T2. For example, as a strength measure, the outer peripheral end of the groove portion 30 may be moved toward the long-side wall frame portions 13C and 13D, so that the groove portion 30 does not include the corners of the reference shape T2. In the following description, the direction in which the reference line SL extends as viewed from the height direction may be referred to as the "extension direction LD" in which the groove portion 30 extends. Furthermore, the direction perpendicular to the extension direction LD and the height direction (Z-axis direction) may be referred to as the width direction WD of the groove portion 30. While FIG. 3 shows the extension direction LD and width direction WD for the corner 14D, similar directions are defined for the other corners 14. The groove 30 penetrates the wall 9 so as to include the positions of the corners of the reference shape T1 on the inner periphery side and the positions of the corners of the reference shape T2 on the outer periphery side. Note that it is sufficient that the groove 30 includes at least one of the corners of the reference shape T1 and the corners of the reference shape T2 when viewed from the height direction. Therefore, the groove 30 does not have to include both the reference shapes T1 and T2.

[0022] At least one of the corners 14A, 14B, 14C, and 14D may have a groove 30. For example, as shown in Figures 4(a) and 4(b), one of the four corners 14A, 14B, 14C, and 14D may have a groove 30. Although the corner 14D has the groove 30 in the figures, the other corners may also have grooves 30.

[0023] Furthermore, at least a pair of diagonally opposite corners may have grooves 30. By providing recesses in the pair of diagonally opposite corners 14, excess component material 20 can flow into the grooves 30 in a balanced manner. The pair of diagonally opposite corners 14 is a combination of corners 14A and 14D and a combination of corners 14B and 14C. In the drawing, the combination of corners 14A and 14D has grooves 30, but the combination of corners 14B and 14C may also have grooves 30.

[0024] At least one of the corners 14 that does not have a groove 30 may have a recess 40 recessed toward the outer periphery from the inner periphery 13a. When viewed from the height direction (the Z-axis direction in this embodiment), the recess 40 has a shape recessed toward the outer periphery on the inner periphery 13a of the cavity 11 of the wall 9. The recess 40 extends from the inner periphery 13a toward the outer periphery 13b, but does not penetrate all the way to the outer periphery 13b. In the drawing, all of the corners 14 where no groove 30 is formed have the recess 40, but some of the corners 14 may have the recess 40.

[0025] Next, with reference to Figures 5(a), (b), and (c), the configuration of the groove portion 30 as viewed from the extension direction LD (see also Figure 3) will be described. Figure 5(a) is a view of a corner 14D between the wall frame portion 13B and the wall frame portion 13D as viewed from the extension direction LD. Note that although Figures 5(a), (b), and (c) show the corner 14D, the same description applies to the other corners 14A, 14B, and 14C. As shown in Figure 5(a), when viewed from the extension direction LD, the groove portion 30 extends from a tip portion 13c in the height direction of the wall frame portions 13B and 13D (in this embodiment, the Z-axis direction) toward the substrate 8 (negative side in the Z-axis direction). The groove portion 30 has a bottom surface 30a and a pair of side surfaces 30b. The bottom surface 30a is formed on the negative side of the Z-axis direction relative to the tip portion 13c. The pair of side surfaces 30b extend from both ends of the bottom surface 30a to the tip end 13c. In the example shown in Fig. 5(a), the groove 30 extends to the main surface 8a of the substrate 8. In this case, the main surface 8a of the substrate 8 forms the bottom surface 30a of the groove 30. In this configuration, the wall frame portion 13B and the wall frame portion 13D are separated by the groove 30.

[0026] As shown in Fig. 5(b), the width of the groove 30 in the width direction WD is larger on the tip end 13c side than on the bottom surface 30a side. The width of the groove 30 at the tip end 13c is larger than the width of the groove 30 at the bottom surface 30a. In the example shown in Fig. 5(b), the groove 30 opens more in the width direction WD toward the tip end 13c side. The pair of side surfaces 30b are inclined so that the distance between them increases toward the positive side in the Z-axis direction.

[0027] 5(c), the bottom surface 30a of the groove portion 30 may be disposed at a position separated from the base material 8. Between the bottom surface 30a and the main surface 8a of the base material 8, the members of the wall frame portions 13B and 13D are present.

[0028] As shown in Figures 6(a) and 6(b), the edges of the groove portion 30 are rounded (corners R). As shown in Figure 6(a), the edge portion 31 between the tip portion 13c and the side surface 30b is rounded. The edge portion 32 between the bottom surface 30a and the side surface 30b is rounded. As shown in Figure 6(b), the edge portion 33 between the inner peripheral surface 13a and the side surface 30b is rounded. The edge portion 34 between the outer peripheral surface 13b and the side surface 30b is rounded.

[0029] As shown in Figures 7(a) and 7(b), when viewed from the height direction, the width of the groove portion 30 in the extension direction LD of the groove portion 30 and the width direction WD perpendicular to the height direction may be larger on one of the outer and inner sides than on the other. For example, in the example shown in Figure 7(a), the width of the groove portion 30 increases from the inner side to the outer side. The distance between the side surfaces 30b on both sides in the width direction WD increases toward the outer side. In this case, the width of the groove portion 30 is larger on the outer side than on the inner side. In the example shown in Figure 7(b), the width of the groove portion 30 increases from the outer side to the inner side. The distance between the side surfaces 30b on both sides in the width direction WD increases toward the inner side. In this case, the width of the groove portion 30 is larger on the inner side than on the outer side.

[0030] As shown in FIG. 7C , when viewed from the height direction, the width of the groove portion 30 in the extension direction LD of the groove portion 30 and the width direction WD perpendicular to the height direction is expressed as W1, the width at the inner circumferential side in the extension direction LD is expressed as W2, and the width at the outer circumferential side is expressed as W3. Either "W1, W3 ≧ W2, W3 ≧ W1" or "W1, W3 ≧ W2, W1 ≧ W3" may be satisfied. W1 is the opening width of the groove portion 30 at the inner circumferential surface 13a. W3 is the opening width of the groove portion 30 at the outer circumferential surface 13b. W2 is the minimum width of the groove portion 30 in the extension direction LD between the inner circumferential surface 13a and the outer circumferential surface 13b. The width of the groove portion 30 will be described in more detail later. The relationship "W1, W3 ≧ W2" means that the width at the intermediate position in the extension direction LD is equal to or less than the opening widths on the inner circumferential side and the outer circumferential side. The opening width on the outer circumferential side and the opening width on the inner circumferential side may be the same, or either may be larger, so "W3≧W1" or "W1≧W3" holds true.

[0031] Next, the size of the groove portion 30 will be described in more detail with reference to FIGS. 3, 8, and 9(a) and 9(b). With reference to FIG. 3, the total area of ​​the inner circumferential surfaces 13a of the wall frame portions 13A, 13B, 13C, and 13D within the wall 9 when viewed from the thickness direction of the wall frame portions 13A, 13B, 13C, and 13D is defined as S. The thickness direction of the wall frame portions 13A and 13B is the X-axis direction. The width of the wall frame portions 13A and 13B when viewed from the thickness direction is the length of the short side of the reference shape T1 and is indicated by Li. The thickness direction of the wall frame portions 13C and 13D is the Y-axis direction. The width of the wall frame portions 13C and 13D when viewed from the thickness direction is the length of the long side of the reference shape T1 and is indicated by Wi. The height of the wall 9 is defined as H (see FIG. 8). In this case, the area S can be calculated by multiplying the total width of the wall frame portions 13A, 13B, 13C, and 13D by the height H of the wall 9. That is, it can be calculated using the following formula (3). Note that the widths of the outer periphery of the wall 9 are Wo and Lo. S = (Wi + Wi + Li + Li) × H (3)

[0032] Next, dimensions of the groove portion 30 will be described with reference to FIGS. 8 and 9(a) and 9(b). Here, an example will be described in which the width is smallest at a midpoint in the extension direction LD, as shown in FIG. 7(c). When the component 20 passes through the groove portion 30, the influence of the narrowest portion as viewed from the extension direction LD becomes greater, and therefore the influence of the portion corresponding to width W2 (see FIG. 7(c)) becomes greater. As shown in FIG. 8, of the widths of the bottom surface 30a of the groove portion 30 in the width direction WD, the width corresponding to width W2 at the midpoint is defined as W2b, the width corresponding to width W1 of the opening on the inner periphery is defined as W1b, and the width corresponding to the opening on the outer periphery is defined as W3b. Of the widths of the tip end portion 13c of the groove portion 30 in the width direction WD, the width corresponding to width W2 at the midpoint is defined as W2t, the width corresponding to width W1 of the opening on the inner periphery is defined as W1t, and the width corresponding to the opening on the outer periphery is defined as W3t. The length of the groove 30 in the extension direction LD at the bottom surface 30a of the groove 30 is denoted by Lb (see FIGS. 9(a) and 9(b)).

[0033] Here, the widths W1b, W2b, and W3b and the length Lb will be described in more detail with reference to FIGS. 9( a) and 9(b). Each dimension is set based on the line of sight VL when viewing the groove portion 30 from inside the wall 9 in the direction along the extension direction LD. The same explanation applies to the widths W1t, W2t, and W3t and the length Lt at the tip portion 13c. FIG. 9(a) illustrates a configuration in which the side surface 30b on the wall frame portion 13B side and the side surface 30b on the wall frame portion 13D side are symmetrical with respect to the reference line SL. Points P1B, P2B, and P3B are defined on the side surface 30b on the wall frame portion 13B side, defining the widths W1b, W2b, and W3b. Points P1D, P2D, and P3D are defined on the side surface 30b on the wall frame portion 13D side, defining the widths W1b, W2b, and W3b. The extension direction LD is set as follows. First, when viewed from the height direction, a line segment connecting a midpoint P3M between points P3B and P3D and a midpoint P1M between points P1B and P1D is defined as a line segment ML. In this case, the length of the line segment ML is defined as "length Lb." Furthermore, a direction parallel to the line segment ML is defined as the extension direction LD of the groove portion 30. A direction perpendicular to the line segment ML when viewed from the height direction is defined as the width direction WD. The distance between a line passing through point P2B and parallel to the extension direction LD and a line passing through point P2D and parallel to the extension direction LD is defined as "width W2b." The distance between a line passing through point P3B and parallel to the extension direction LD and a line passing through point P3D and parallel to the extension direction LD is defined as "width W3b." The distance between a line passing through point P1B and parallel to the extension direction LD and a line passing through point P1D and parallel to the extension direction LD is defined as "width W1b."

[0034] 9(a) and 9(b), the line segment connecting points P1B and P1D, the line segment connecting points P2B and P2D, and the line segment connecting points P3B and P3D are all perpendicular to the reference line SL. Therefore, the distance between points P1B and P1D when viewed from the height direction is equal to the width W1b in the width direction WD. The distance between points P2B and P2D when viewed from the height direction is equal to the width W2b in the width direction WD. The distance between points P3B and P3D when viewed from the height direction is equal to the width W3b in the width direction WD. The length Lb of the groove portion 30 on the bottom surface 30a is set as the distance in the extension direction LD between points P1B and P1D and points P3B and P3D.

[0035] FIG. 9B illustrates a configuration in which the side surface 30b on the wall frame portion 13B side and the side surface 30b on the wall frame portion 13D side are asymmetric with respect to the reference line SL. Here, the side surface 30b on the wall frame portion 13D side is positioned farther away from the reference line SL than the side surface 30b on the wall frame portion 13B side. In this case, the line segment connecting points P1B and P1D, the line segment connecting points P2B and P2D, and the line segment connecting points P3B and P3D are not perpendicular to the reference line SL. Therefore, the distance between points P1B and P1D when viewed from the height direction is greater than the width W1b in the width direction WD. The distance between points P2B and P2D when viewed from the height direction is greater than the width W2b in the width direction WD. The distance between points P3B and P3D when viewed from the height direction is greater than the width W3b in the width direction WD. 9(b), the line segment ML, the extension direction LD, and the width direction WD are set in the same manner as described in FIG. 9(a), and the widths W1b, W2b, and W3b and the length Lb are set. Note that FIGS. 9(a) and 9(b) are merely examples of the shape of the side surface 30b, and various other shapes can be adopted.

[0036] As shown in FIG. 8 , the opening area of ​​the groove portion 30 when viewed from the extension direction LD of the groove portion 90 within the wall 9 is designated as Sc. The opening area Sc is the hatched portion in FIG. 8 . When viewed from the extension direction LD, the opening area Sc is the area of ​​the region surrounded by the side surface 30b, the bottom surface 30a, and a reference line STL, which is a virtual line extending from the tip portion 13c. The opening area Sc is defined by a line segment drawn by the innermost portion of the side surfaces 30b on both sides in the width direction WD. The depth of the groove portion 30 is designated as Hs. The opening area Sc shown in FIG. 8 is calculated using the following formula (4). However, in the case of a configuration such as that shown in FIG. 5( a) or FIG. 6( a), calculations can be performed to determine the opening area Sc corresponding to each structure. Note that the lower limit of the width W2b, which corresponds to the minimum width of the groove portion 30, is not particularly limited, but may be, for example, 1 μm or more, or 4 μm or more. The upper limit may be set within a range that satisfies the formulas (1) and (2) described below. When the bottom surface 30a is disposed at a position separated from the substrate 8, the bottom surface 30a may have a curved shape. Sc={(W2t+W2b)×Hs} / 2 (4)

[0037] The relationship of the following formula (1) holds between the area S of the wall frame portions 13A, 13B, 13C, and 13D calculated as above and the opening area Sc. Furthermore, as described above, if the width of the bottom surface 30a of the groove portion 30 in the width direction WD is W2b and the length of the groove portion 30 in the extension direction LD at the bottom surface 30a of the groove portion 30 is Lb, the following formula (2) holds. Note that "n" in formula (2) refers to the total number of groove portions 30 included in the wall 9. In the embodiment shown in FIG. 3, there are four groove portions 30, so "n = 4". Furthermore, for example, in the example shown in FIGS. 7(a) and 7(b), the narrower width dimension of the opening on the inner circumferential side or the outer circumferential side is "W2b". 0.004≦Sc / S<0.6 (1) 0.1≦Σ(W2bn / Lbn)<21.5 (2)

[0038] As shown in FIG. 10A , one of the surfaces of the wall 9 extending in the height direction may have a recess 45 located closer to the substrate 8 in the height direction, and a cavity material 46 covering the substrate 8 may be provided at the position of the recess 45. The surfaces of the wall 9 extending in the height direction are the inner peripheral surface 13 a, the outer peripheral surface 13 b, and the side surface 30 b of the groove 30. It is sufficient that any of these surfaces 13 a, 13 b, and 30 b has the recess 45. Furthermore, the recess 45 does not need to be provided over the entire area of ​​each surface 13 a, 13 b, and 30 b; it is sufficient that it is provided only on a portion of each surface. The recess 45 is formed closer to the substrate 8 in the height direction than the tip 13 c. The recess 45 is formed at a position spaced upward from the main surface 8 a of the substrate 8. Thus, the cavity material 46 is formed between the recess 45 and the main surface 8 a of the substrate 8. The recessed portion 45 may extend in a direction in which the surfaces 13a, 13b, and 30b extend along the planar direction of the base material 8. For example, if the inner peripheral surface 13a of the wall frame portion 13A has the recessed portion 45, the recessed portion 45 may be formed to extend in the Y-axis direction. Furthermore, if the side surface 30b of the groove portion 30 of the corner portion 14D has the recessed portion 45, the recessed portion 45 may be formed to extend in the extension direction LD (see FIG. 3 ).

[0039] The opening width of the recess 45, i.e., the height dimension w1 of the opening, is not particularly limited but may be set to 0 μm or more and 3 μm or less. The thickness of the cavity material 46, i.e., the height dimension w2, is not particularly limited but may be set to 0 μm or more and 1 μm or less. The depth dimension D1 of the recess 45 is not particularly limited but may be set to 0 μm or more and 3 μm or less. In the example shown in FIG. 10( b), the recess 45 is formed at the position of the substrate 8, and no cavity material 46 is formed. Such a structure reduces the bonding strength between the wall 9 and the substrate 8, so the structure shown in FIG. 10( a) is preferable. However, the structure shown in FIG. 10( b) is not excluded.

[0040] A manufacturing method for the circuit board 3 and the mounting board 1 will be described with reference to FIGS. 11( a), 11( b), 11( c), and 12. First, as shown in FIG. 11( a), terminals 10 are formed on the upper surface of the substrate 8. Next, as shown in FIG. 11( b), walls 9 are formed on the substrate 8. This completes the circuit board 3. In FIG. 11( b), a conductive film 12 and a bonding material 4A are formed on the upper surface of the terminal 10. Next, as shown in FIG. 11( c), the component 20 is filled into the cavity 11, thereby placing the component 20 on the substrate 8. Then, the electronic component 2 is held by a holding member and mounted in the cavity 11. Next, as shown in FIG. 12, the electronic component 2 is pressed into the cavity 11 using a pressure reflow device 49, bringing the bonding material 4A and the bonding material 4B into contact inside the component 20. At this time, a portion of the component 20 is pushed into the groove 30 (see FIG. 3). Next, the bonding material 4B of the electronic component 2 is bonded to the bonding material 4A of the base material 8 by heating. In this way, the mounting substrate 1 is completed.

[0041] The circuit board 3 may include a bonding material 4A (first bonding material) containing a metal element disposed on the terminal 10A, and a bonding material 4A (second bonding material) containing a metal element disposed on the terminal 10B. In this case, the electronic component 2 can be mounted on the terminals 10A and 10B via the bonding material 4A.

[0042] Next, a method for forming a wall 9 having a groove portion 30 will be described with reference to Figures 13(a), (b), (c), (d), (e), and (f). First, as shown in Figure 13(a), a wall 9 is formed on a substrate 8. Next, as shown in Figure 13(b), a laser is irradiated onto the wall 9 using a laser device 51, thereby processing a portion of the wall 9. As a result, a groove portion 30 is formed in the wall 9, as shown in Figure 13(c).

[0043] Alternatively, as shown in Fig. 13(d), a resist 52 is formed on the substrate 8. Next, as shown in Fig. 13(e), exposure is performed using a glass mask 53 having a pattern corresponding to the shape of the wall 9 having the groove 30. As shown in Fig. 13(f), the exposed resist 52 is developed to form the wall 9 having the groove 30.

[0044] When forming an undercut portion (a recessed portion as shown in FIGS. 10(a) and 10(b)), the focus position of the exposure light may be shifted above the film surface. Alternatively, the undercut portion may be formed by overdeveloping. When the groove portion 30 does not reach the substrate 8, as in FIG. 5(c), the groove portion 30 may be formed by scraping off only the surface of the wall 9 with a laser or the like.

[0045] Next, the functions and effects of the method for manufacturing the circuit board 3 and the mounting board 1 according to this embodiment will be described.

[0046] First, a circuit board 103 according to a comparative example will be described with reference to Fig. 14. The wall 9 of the circuit board 103 does not have the groove 30 described above. After filling the interior of the wall 9 with the component 20, if an electronic component 2 is mounted inside the wall 9 using a holding member and an attempt is made to press the electronic component 2 into the wall 9 using a pressure reflow device, the electronic component 2 cannot be pressed in sufficiently due to the influence of the excess component 20. In this case, reflow is performed with the bonding material 4B of the electronic component 2 and the bonding material 4A of the circuit board 3 still spaced apart, which could result in poor connection between the bonding material 4A of the circuit board 3 and the electronic component 2.

[0047] In contrast, in the circuit board 3 according to this embodiment, a pair of terminals 10 (first and second terminals) are disposed within a cavity 11 surrounded by a wall 9. The wall 9 has a groove 30 extending from the inner peripheral surface 13 a to the outer peripheral surface 13 b. In this case, a component 20 is disposed within the cavity 11, an electronic component 2 is mounted using a holding member, and the electronic component 2 is pressed into the cavity 11 using a pressure reflow soldering device and heated to bond it to the circuit board 3. When the electronic component 2 is mounted on the circuit board 3, excess component 20 can be expelled through the groove 30 to the outside of the wall 9. This allows the electronic component 2 to be sufficiently pressed into the cavity 11 and brought into contact with the bonding material 4 during the pressure application process using the pressure reflow soldering device. The cavity 11 within the wall 9 can be used as a mechanism for positioning the electronic component 2. If the inner peripheral surface 13 a of the wall frame 13 has a large groove, distortion may occur in the inner peripheral surface 13 a. In contrast, at least one of the corners 14 formed by the two wall frame portions 13 of the wall 9 has a groove 30. In this case, the wall frame portion 13 does not have the groove 30 (or even if it does have one, it can be made small), which prevents distortion of the inner circumferential surface 13a. Therefore, the electronic component 2 can be accurately positioned using the inner circumferential surface 13a of the wall frame portion 13. As a result, poor connection between the circuit board 3 and the electronic component 2 can be prevented, and the positional accuracy of the mounted electronic component 2 can be improved.

[0048] The wall 9 has wall frame portions 13 provided on all four sides, thereby having four corners 14, and of the four corners 14, at least a pair of diagonally opposite corners 14 have grooves 30, or all four corners 14 may have grooves 30. The corners 14 of the cavity 11 are the locations to which the most pressure of the constituent material 20 is applied, so providing grooves 30 in these locations makes it easier to pour in excess constituent material 20. Furthermore, by having grooves 30 in at least a pair of diagonally opposite corners 14, excess constituent material 20 can be poured out of the grooves in a balanced manner.

[0049] When viewed from the extension direction of the groove 30, the groove 30 extends from the tip 13c in the Z-axis direction (first direction) of the wall frame 13 toward the base 8, and the bottom surface 30a of the groove 30 may be located at a position spaced apart from the base 8. In this case, the wall frame portions 13 that form the corners 14 are connected to each other on the base 8 side, thereby improving the strength of the wall 9 and the positioning accuracy of the cavity 11.

[0050] At least one of the inner peripheral surface 13a, the outer peripheral surface 13b of the wall frame portion 13, and the side surface 30b of the groove portion 30 has a recessed portion 45 located on the substrate 8 side in the Z-axis direction, and a cavity material 46 covering the substrate 8 may be provided at the position of the recessed portion 45. With this shape, the recessed portion 45 can function as a guide groove through which the component material 20 passes at the position on the substrate 8 side. This can improve the fluidity of the component material 20.

[0051] When the total area of ​​the inner peripheral surface 13a of the wall frame portion 13 when viewed in the thickness direction of the wall frame portion 13 within the wall 9 is S, the opening area of ​​the groove portion 30 when viewed in the extension direction LD of the groove portion 30 within the wall 9 is Sc, the width of the bottom surface 30a of the groove portion 30 in the width direction WD perpendicular to the extension direction LD and the Z-axis direction is W2b, and the length of the groove portion 30 in the extension direction LD at the bottom surface 30a of the groove portion 30 may be Lb, the following formulas (1) and (2) may be established. Establishing formula (1) prevents the component material 20 from becoming difficult to flow due to an opening area ratio that is too small, and prevents the required amount of component material 20 from flowing out due to an opening area ratio that is too large. Furthermore, since formula (2) is satisfied, it is possible to prevent the component material 20 from becoming difficult to flow due to an increase in pressure loss caused by the width W2b becoming narrower relative to the length Lb, which is the flow path length, and to prevent the necessary amount of component material from flowing out due to the width W2b being too wide. 0.004≦Sc / S<0.6 (1) 0.1≦Σ(W2bn / Lbn)<21.5 (2)

[0052] When viewed from the thickness direction of the wall frame 13, the groove 30 extends from the tip of the wall frame 13 toward the base material 8 in a first direction perpendicular to the main surface 8a of the base material 8, and the width of the groove 30 in the width direction perpendicular to the thickness direction and the first direction may be larger on the tip 13c side than on the bottom surface 30a side. In this case, narrowing the groove 30 on the base material 8 side increases the flow resistance, allowing the necessary components to be retained, and widening the groove 30 on the tip side makes it easier to discharge excess components.

[0053] When viewed from the Z-axis direction, the width of the groove 30 in the extension direction LD of the groove 30 and in the width direction WD perpendicular to the Z-axis direction may be larger on either the outer circumferential side or the inner circumferential side than on the other side. In this case, the flowability of the component material 20 flowing through the groove 30 from the inner circumferential side to the outer circumferential side can be controlled by the width of the groove 30. This also makes it possible to suppress distortion of the wall 9 and improve the positioning accuracy of the cavity 11.

[0054] When viewed from the Z-axis direction, the width of the groove 30 in the extension direction LD of the groove 30 and the width direction W perpendicular to the Z-axis direction is expressed as W1, the width at a midpoint in the extension direction is expressed as W2, and the width at the outer periphery is expressed as W3. Either "W1, W3 ≧ W2, W3 ≧ W1" or "W1, W3 ≧ W2, W1 ≧ W3" may be satisfied. In this case, the flowability of the component 20 flowing through the groove 30 from the inner periphery to the outer periphery can be controlled by the width of each position of the groove 30. This also suppresses distortion of the wall 9, improving the positioning accuracy of the cavity 11.

[0055] At least one of the corners 14 where no groove 30 is formed may have a recess 40 recessed toward the outer periphery of the inner periphery. For example, as shown in Fig. 15(a), if the corner does not have a recess 40, there is a possibility that the corner of the electronic component 2 will interfere with a corner in the cavity 11 before the electronic component 2 comes into contact with the inner periphery. On the other hand, as shown in Fig. 15(b), the corner 14 of the cavity 11 has a recess 40, which can prevent the corner 14 of the cavity 11 from interfering with the corner of the electronic component 2.

[0056] The edges of the grooves 30 may be rounded. In this case, it is possible to prevent the component 20 from receiving resistance from the edges during flow.

[0057] The method for manufacturing the mounting board 1 according to this embodiment is a method for manufacturing the mounting board 1 by mounting the electronic components 2 on the circuit board 3 described above, in which the components 20 are placed on the base material 8, the electronic components 2 are placed, and then the electronic components 2 are joined to the terminals 10 using a pressure reflow device 49.

[0058] In this case, the same functions and effects as those of the circuit board 3 described above can be obtained.

[0059] The present disclosure is not limited to the above-described embodiment. For example, the number and arrangement of terminals on the circuit board are not particularly limited. Furthermore, although one electronic component 2 is arranged within the wall 9 in the above-described embodiment, multiple electronic components 2 may be arranged within the wall 9. The arrangement of the multiple electronic components 2 is not particularly limited.

[0060] [Examples] Examples of the mounting board according to the present disclosure will be described below, but the present disclosure is not limited to the following examples.

[0061] First, the mounting boards of the comparative example and examples 1 to 6 were fabricated using the following manufacturing method. First, a wall 9 having a groove 30 at the corner was formed on a base material 8 so as to surround the terminal 10 and the bonding material 4, thereby obtaining a circuit board 3. Next, a component 20 was filled into the circuit board 3, and an LED chip was mounted as the electronic component 2. Next, the mounting board 1 in this state was pressurized at 0.01 MPa in a pressure reflow device 49 and reflowed at 150°C to 190°C. This resulted in the circuit board 3 and electronic component 2 being bonded together. Various conditions for the comparative example and examples 1 to 6 are shown in Tables 1 to 3. In Table 1, the "intra-wall opening width Wi" refers to the longitudinal dimension of the reference shape T1 on the inner periphery of the wall 9 (see FIG. 3). The "intra-wall opening width Li" refers to the lateral dimension of the reference shape T1 on the inner periphery of the wall 9 (see FIG. 3). The "wall frame width Top:Ltw" is the thickness of the wall frame portions 13C and 13D on the long side of the wall 9. The "wall frame width Tip:Ltl" is the thickness of the wall frame portions 13A and 13B on the short side of the wall 9. The "wall exterior opening width Wo" is the longitudinal dimension of the reference shape T2 on the outer periphery of the wall 9 (see FIG. 3). The "wall exterior opening width Lo" is the lateral dimension of the reference shape T2 on the outer periphery of the wall 9 (see FIG. 3). The "groove position" in Table 2 indicates the position of the groove 30. "None" means that the groove 30 is not formed, "two corners" means that the groove 30 is formed at the corners 14A and 14D, "one corner" means that the groove 30 is formed at the corner 14D, and "square" means that the groove 30 is formed at all four corners 14. "Groove Top Width: W2t" is the width of the groove 30 on the tip 13c side (see FIG. 8). "Groove Bottom: W2b" is the width of the groove 30 on the bottom surface 30a side (see FIG. 8). "Wall Height: H" is the height of the wall 9 (see FIG. 8). "Groove Depth: Hs" is the depth of the groove 30 (see FIG. 8). "S", "Sc", "Sc / S", and "ΣW2bn / Lbn" in Table 3 correspond to the above-mentioned formulas (1) and (2).

[0062] Table 3 shows the evaluation results for the comparative example and examples 1 to 6. The evaluation results shown in Table 3 are for the number of sample circuit boards 3 shown in the "Number of Mounted" column, which were then mounted with electronic components 2. The "Wall Peeling Failure" column in Table 3 indicates whether or not there were any samples in which the wall 9 peeled off from the substrate 8. There was no peeling in any of the comparative example and examples 1 to 6. "OK" indicates the number of samples in which electronic components 2 could be mounted on the circuit board 3, and the "Electronic Component Mounting Rate" indicates the percentage of OK products relative to the total number of samples. While the comparative example had a low electronic component mounting rate of 10.7%, the mounting rate was 100% in all of examples 1 to 6.

[0063] [Mode 1] A circuit board comprising: a substrate having a main surface; first and second terminals provided on the main surface of the substrate; and one or more walls made of insulating material provided on the main surface of the substrate, wherein the first and second terminals are arranged in a cavity surrounded by the walls, and at least one of the corners formed by two wall frame portions of the walls has a groove portion penetrating from the inner circumferential surface to the outer circumferential surface. [Mode 2] The circuit board according to Mode 1, wherein the wall has wall frame portions provided on all four sides, thereby providing four corners, and among the four corners, at least a pair of diagonally adjacent corners has the groove portion, or all four corners have the groove portion. [Mode 3] The circuit board according to Mode 1 or 2, wherein, when viewed from the extension direction of the groove portion, the groove portion extends from a tip end of the wall frame portion toward the substrate in a first direction perpendicular to the main surface of the substrate, and a bottom surface of the groove portion is located at a position spaced from the substrate. [Mode 4] The circuit board according to any one of Modes 1 to 3, wherein at least one of an inner peripheral surface, an outer peripheral surface of the wall frame portion, and a side surface of the groove portion has a recessed portion located on the substrate side in a first direction orthogonal to the main surface of the substrate, and a cavity material covering the substrate is provided at the position of the recessed portion. [Mode 5] The circuit board according to any one of Modes 1 to 4, wherein the circuit board according to any one of Modes 1 to 4, wherein the circuit board according to any one of Modes 1 to 4, wherein the circuit board according to any one of Modes 1 to 4, 0.004≦Sc / S<0.6 (1) 0.1≦Σ(W2bn / Lbn)<21.5 (2) [Mode 6] The circuit board according to any one of Modes 1 to 5, wherein, when viewed in the thickness direction of the wall frame portion, the groove portion extends from a tip end of the wall frame portion in a first direction orthogonal to the main surface of the base material toward the base material, and a width of the groove portion in a width direction orthogonal to the thickness direction and the first direction is larger on the tip end side than on the bottom surface side.[Mode 7] The circuit board according to any one of Modes 1 to 6, wherein, as viewed from a first direction orthogonal to the main surface of the base, the width of the groove in the extension direction of the groove and in the width direction orthogonal to the first direction is larger on one of the outer peripheral side and the inner peripheral side than on the other. [Mode 8] The circuit board according to any one of Modes 1 to 7, wherein, as viewed from the first direction orthogonal to the main surface of the base, the width of the groove in the extension direction of the groove and in the width direction orthogonal to the first direction is defined as W1, the width at a midpoint in the extension direction is defined as W2, and the width of the groove in the outer peripheral side is defined as W3, where W1 is the width on the inner peripheral side, W2 is the width at a midpoint in the extension direction, and W3 is the width on the outer peripheral side. [Mode 9] The circuit board according to any one of Modes 1 to 8, wherein at least one of the corners where the groove is not formed has a recess recessed outward from the inner peripheral surface. [Mode 10] The circuit board according to any one of Modes 1 to 9, wherein edges of the groove are rounded. [Mode 11] A method for manufacturing a mounted board by mounting electronic components on the circuit board according to any one of Modes 1 to 10, comprising arranging components on the base material, arranging the electronic components, and then bonding the electronic components to the terminals using a pressure reflow machine.

[0064] 1...mounting board, 2...electronic component, 3...circuit board, 4A...bonding material, 8...substrate, 9...wall, 10...terminal, 11...cavity, 13...wall frame portion, 14...corner portion, 20...component material, 30...groove portion, 40...recess, 45...dent portion, 46...cavity material, 49...pressure reflow device.

Claims

1. A circuit board comprising: a substrate having a main surface; a first terminal and a second terminal provided on the main surface of the substrate; and one or more walls made of an insulating material provided on the main surface of the substrate, wherein the first and second terminals are disposed within a cavity surrounded by the walls, and at least one of the corners formed by two wall frame portions of the walls has a groove portion penetrating from an inner peripheral surface to an outer peripheral surface.

2. A circuit board as described in claim 1, wherein the wall has a wall frame portion provided on all four sides, thereby having four corners, and among the four corners, at least a pair of diagonally opposite corners have the groove portion, or all of the four corners have the groove portion.

3. The circuit board according to claim 1, wherein, when viewed from the extension direction of the groove portion, the groove portion extends from a tip end of the wall frame portion in a first direction perpendicular to the main surface of the base material toward the base material, and a bottom surface of the groove portion is positioned at a position spaced apart from the base material.

4. The circuit board according to claim 1, wherein at least one of the inner peripheral surface, the outer peripheral surface and the side surface of the groove portion has a recessed portion at a position on the substrate side in a first direction perpendicular to the main surface of the substrate, and a cavity material covering the substrate is provided at the position of the recessed portion.

5. The circuit board according to claim 1, wherein the following formulas (1) and (2) are established, where S is the total area of ​​the inner peripheral surface of the wall frame portion when viewed in the thickness direction of the wall frame portion within the wall, Sc is the opening area of ​​the groove portion when viewed in the extending direction of the groove portion within the wall, W2b is the width of the bottom surface of the groove portion in a width direction perpendicular to the extending direction and a first direction perpendicular to the main surface of the base material, and Lb is the length of the groove portion in the extending direction at the bottom surface of the groove portion. 0.004≦Sc / S<0.6 ... (1) 0.1≦Σ(W2bn / Lbn)<21.5 ... (2) 6. The circuit board according to claim 1, wherein, when viewed in a thickness direction of the wall frame portion, the groove portion extends from a tip end of the wall frame portion in a first direction perpendicular to the main surface of the base material toward the base material, and the width of the groove portion in a width direction perpendicular to the thickness direction and the first direction is larger on the tip end side than on the bottom surface side.

7. The circuit board according to claim 1, wherein, when viewed from a first direction perpendicular to the main surface of the base material, the width of the groove in the extension direction of the groove and in a width direction perpendicular to the first direction is larger on one of the outer peripheral side and the inner peripheral side than on the other.

8. The circuit board according to claim 1, wherein, when viewed from a first direction perpendicular to the main surface of the base material, the width of the groove portion in the extension direction of the groove portion and in a width direction perpendicular to the first direction is W1, the width at a midpoint in the extension direction is W2, and the width at the outer periphery is W3, then one of "W1, W3≧W2, W3≧W1" or "W1, W3≧W2, W1≧W3" is satisfied.

9. The circuit board according to claim 1, wherein at least one of said corners where said groove is not formed has a recess that is recessed toward the outer periphery further than said inner periphery.

10. The circuit board of claim 1, wherein edges of said grooves are rounded.

11. A method for manufacturing a mounted board by mounting electronic components on a circuit board according to any one of claims 1 to 10, comprising arranging components on the base material, arranging the electronic components, and then bonding the electronic components to the terminals using a pressure reflow device.

Images