Circuit board, and method for manufacturing mounting board

Abstract

To provide a circuit board that can prevent a reduction in quality and accurately locate an electronic part, and a method for manufacturing a mounting board.SOLUTION: When an electronic part 2 is mounted on a circuit board 3, the electronic part 2 is inserted into a cavity 11 and thereby joined to terminals 10A, 10B with a joint material 4A. On the circuit board 3, a wall 9 is formed with at least one groove part 30 that penetrates from an inner peripheral surface 13a to an outer peripheral surface 13b. Providing the groove part 30 in the wall 9 can secure the groove part 30 as a space for forming the terminals 10A, 10B. The terminals 10A, 10B have portions arranged on an outer peripheral side from a reference shape T1 through the groove part 30. Using a space on the outer peripheral side of the reference shape T1 can prevent the terminals 10A, 10B from being excessively reduced in size. The degree of difficulty in pattern formation of the terminals 10A, 10B can be reduced to stabilize quality.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] In recent years, with the progress of electronization, the development of technology for mounting electronic components on a substrate has advanced. For example, a technology for mounting a large number of bare chips of semiconductor light-emitting elements typified by light-emitting diodes (hereinafter referred to as "LEDs") used in lighting, display devices, etc. on a wiring board has been developed. For example, Patent Document 1 discloses an invention in which a semiconductor light-emitting element is inserted and joined into a cavity in which a plurality of semiconductor light-emitting elements can be easily positioned and arranged. Further, Patent Document 2 discloses an invention in which an electrode joining portion is provided in a cavity, and an electronic component is inserted into the cavity so as to be joined to the electrode joining portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in a structure such as that of Patent Document 1, problems occur in that the electronic component moves within the cavity, and for example, in an LED element or the like, the orientation of the element becomes uneven. In a configuration such as that of Patent Document 2, when the electronic component is miniaturized, the cavity is also miniaturized accordingly. At this time, it becomes necessary to make the terminals in the cavity small as well. However, forming a small-sized pattern is difficult to form with high positional accuracy due to problems such as the resolution limit of the resist and the exposure apparatus, and there are problems such as a decrease in yield due to a decrease in quality due to dimensional variations.

[0005] The present disclosure aims to provide a circuit board and a method for manufacturing a mounting board that can suppress a decrease in quality and accurately position electronic components.

Means for Solving the Problems

[0006] The circuit board according to the present disclosure includes a base material having a main surface, a first terminal and a second terminal provided on the main surface of the base material, and a wall of an insulating material provided on the main surface of the base material. The wall has at least one groove portion penetrating from the inner peripheral surface to the outer peripheral surface. The first and second terminals are disposed in a cavity surrounded by the wall, and when a rectangular reference shape with the minimum area circumscribing the inner peripheral surface of the wall is set when viewed from a first direction orthogonal to the main surface of the base material, at least one of the first and second terminals has a portion disposed on the outer peripheral side from the reference shape through the groove portion.

[0007] The method for manufacturing a mounting board according to the present disclosure is a method for manufacturing a mounting board by mounting electronic components on the above-described circuit board. After disposing a constituent material on the base material and disposing the electronic components, the electronic components may be joined to the terminals using a pressure reflow device.

Effects of the Invention

[0008] According to the present disclosure, it is possible to provide a circuit board and a method for manufacturing a mounting board that can suppress a decrease in quality and accurately position electronic components.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

DETAILED DESCRIPTION OF THE INVENTION

[0010] With reference to FIGS. 1 to 3, the circuit board 3 according to the embodiment of the present disclosure will be described. FIG. 1 is a schematic cross-sectional view showing a mounting board 1 including the circuit board 3 according to the embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing the circuit board 3 according to the embodiment of the present disclosure. FIG. 3 is a plan view of the circuit board 3.

[0011] As shown in FIG. 1, the mounting board 1 includes an electronic component 2 and a circuit board 3. The mounting board 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 portion 6 and a pair of terminals 7. The main body portion 6 is a member for exerting the function as the electronic component 2. The terminal 7 is a metal portion formed on the main surface of the main body portion 6. As the material of the terminal 7, metals such as Cu, Ti, Au, Ni, Sn, Bi, P, B, In, Ag, Zn, Pd, Mo, Pt, Cr, or an alloy selected from at least two of these may be adopted. The electronic component 2 is constituted by, for example, a micro LED or the like. The micro LED is a component that emits light in response to an input from the circuit board 3.

[0013] The circuit board 3 includes a base material 8, a wall 9, and a pair of terminals 10 (a first terminal and a second terminal). The base material 8 is a flat main body portion of the circuit board 3. The base material 8 has a main surface 8a. As the base material 8, a printed circuit board for mounting each conductor pattern and each electronic component on the circuit board 3 on the main surface 8a may be adopted. As the material of the base material 8, a known resin material or ceramic material used for a printed circuit board may be adopted. In the following description, the description may be made using the XYZ coordinates set for the circuit board 3. The X-axis direction (the second direction) is a direction parallel to the main surface 8a of the base material 8, the Y-axis direction (the third direction) is a direction parallel to the main surface 8a of the base material 8 and orthogonal to the X-axis direction, and the Z-axis direction (the first direction) is a direction orthogonal to the main surface 8a of the base material 8.

[0014] The insulating wall 9 is provided on the main surface 8a of the base material 8. The wall 9 is a member formed of an insulating material. The wall 9 protrudes convexly from the base material 8 toward the positive side in the Z-axis direction. As shown in FIG. 3, in the present embodiment, the wall 9 has wall frame portions 13A, 13B, 13C, and 13D provided on four sides. The wall frame portions 13A and 13B face each other in a state of being spaced apart from each other in the X-axis direction and extend in parallel in the Y-axis direction. The wall frame portion 13A is arranged on the positive side in the X-axis direction, and the wall frame portion 13B is arranged on the negative side. The wall frame portions 13C and 13D face each other in a state of being spaced apart from each other in the Y-axis direction and extend in parallel in the X-axis direction. The wall frame portion 13C is arranged on the positive side in the Y-axis direction, and the wall frame portion 13D is arranged on the negative side. The wall frame portion 13A connects the ends on the positive side in the X-axis direction of the wall frame portions 13C and 13D. The wall frame portion 13B connects the ends on the negative side in the X-axis direction of the wall frame portions 13C and 13D. Thereby, the wall 9 has a rectangular frame-like structure when viewed from the Z-axis direction. The wall frame portions 13A and 13B constitute the short sides, and the wall frame portions 13C and 13D constitute the long sides. Although 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 inside the wall 9 may be set to be 8 μm or more and 44 μm or less. The dimension of the long side of the inner peripheral surface inside the wall 9 may be 15 μm or more and 68 μm or less. The dimension of the short side of the inner peripheral surface inside 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 inside 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. As the material of the wall 9, for example, resin materials such as epoxy resin, acrylic resin, phenolic resin, melamine resin, urea resin, and alkyd resin are adopted. Particularly preferably, epoxy resin and acrylic resin are adopted as the material of the wall 9.

[0015] As shown in FIGS. 1 to 3, the terminal 10 is a metal part provided on the main surface 8a of the base material 8. As the material of the terminal 10, Ni, Cu, Ti, Cr, Al, Mo, Pt, Au, or an alloy selected from at least two of these is adopted. A conductive film 12 is formed on the upper surface of the terminal 10. As the material of the conductive film 12, a film such as Ti, Cu, Ni, Al, Mo, Cr, Ag, or a film in which metal particles and a binder are mixed is adopted.

[0016] The bonding material 4 is a member that bonds the terminal 7 of the electronic component 2 and the terminal 10 of the circuit board 3. The bonding material 4 is configured 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. 6). 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 one containing Sn. The bonding material 4 may be composed of an alloy containing an element that lowers the melting point of Sn in addition to Sn. Examples of the element that lowers the melting point of Sn include Bi. The bonding material 4 functions as solder. As a result, between the base material 8 and the main body portion 6, the terminal 10, the conductive film 12, the bonding material 4, and the terminal 7 are laminated in order from the upper surface of the base material 8. Note that, at this location, soldering is performed after the terminal 10, the conductive film 12, the bonding material 4, and the terminal 7 are laminated. Therefore, after soldering, a structure in which the metals of the terminal 10, the conductive film 12, the bonding material 4, and the terminal 7 are melted and diffused is formed. Such a structure after soldering may be a structure containing brittle intermetallic compounds (IMC). When brittle intermetallic compounds exist, they are likely to break due to external stress, so the reliability is likely to decrease. Therefore, by surrounding the electronic component 2 with the wall 9, the effect of protecting the electronic component 2 appears.

[0017] A cavity 11 is formed in the wall 9. The cavity 11 is constituted by a through-hole that penetrates the wall 9 in the Z-axis direction. Thereby, on the bottom side of the cavity 11, the upper surface of the base material 8 is exposed. The cavity 11 forms a rectangle when viewed from the Z-axis direction (see FIG. 3). The terminal 7, the terminal 10, the conductive film 12, and the bonding material 4 are arranged within the cavity 11 surrounded by the wall 9, and thus are surrounded by the wall 9 on all sides. A slight gap is formed between the terminal 7, the terminal 10, the conductive film 12, the bonding material 4, and the inner peripheral surface 13a of the four-sided wall frame portions 13A, 13B, 13C, 13D that constitute the cavity 11.

[0018] Within the cavity 11, a structural member 20 is arranged between the electronic component 2 and the bonding material 4 and the wall 9. Thereby, by being supported by the structural member 20, the electronic component 2 can be made difficult to peel off from the circuit board 3. In addition, the forces applied to the electronic component 2, the bonding material 4, and the terminals 7, 10 can be alleviated, and the reliability can be improved. As the material of the structural member 20, for example, epoxy resin, acrylic resin, phenolic resin, melamine resin, urea resin, alkyd resin, or a mixture thereof, or a mixture of the resin material and SiOx, ceramics, etc. is adopted. Particularly preferably, epoxy resin and acrylic resin are adopted as the material of the structural member 20. The viscosity of the structural member 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 structural member 20 are removed from the mounting board 1 shown in FIG. 1. In the circuit board 3, a bonding material 4A containing a metal element is arranged on the upper side of the terminal 10 (the upper surface of the conductive film 12). The circuit board 3 includes a bonding material 4A (the first bonding material) on the side in the X-axis direction arranged on the terminal 10A, and a bonding material 4A (the second bonding material) on the negative side in the X-axis direction arranged on the terminal 10B. These bonding materials 4A constitute a part of the bonding material 4 in the stage before thermally bonding the electronic component 2 and the mounting board 1 as described above. In the state of the circuit board 3, the pair of terminals 10, the conductive film 12, and the bonding material 4A are arranged within the wall 9 formed of an insulator.

[0020] As shown in FIG. 3, the wall 9 has at least one groove portion 30 that penetrates from the inner peripheral surface 13a to the outer peripheral surface 13b. In the present embodiment, the wall 9 has one groove portion 30A in the wall frame portion 13C and one groove portion 30B in the wall frame portion 13D. For the wall frame portions 13C and 13D, the Y-axis direction is the thickness direction. Therefore, the groove portions 30A and 30B of the wall frame portions 13C and 13D extend in the Y-axis direction and penetrate the wall frame portions 13C and 13D. Note that the groove portion 30 only needs to be formed in at least one of the wall frame portions 13A, 13B, 13C, and 13D. Also, a plurality of groove portions 30 may be formed in any of the wall frame portions 13A, 13B, 13C, and 13D. Further, the groove portion 30 may be formed at the corner portion of each of the wall frame portions 13A, 13B, 13C, and 13D (details will be described later).

[0021] Next, with reference to FIG. 4, the configuration when the wall frame portion 13C is viewed from the thickness direction will be described. FIG. 4(a) is a view of the wall frame portion 13C viewed from the Y-axis direction, which is the thickness direction. Although the wall frame portion 13C is shown in FIG. 4, the same description also applies to the other wall frame portion 13D. As shown in FIG. 4(a), when viewed from the Y-axis direction, which is the thickness direction of the wall frame portion 13C, the groove portion 30 extends from the tip portion 13c in the height direction (Z-axis direction in the present embodiment) of the wall frame portion 13C toward the base material 8 side (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 in the Z-axis direction rather than the tip portion 13c. The pair of side surfaces 30b extend from both ends in the X-axis direction of the bottom surface 30a to the tip portion 13c. In the example shown in FIG. 4(a), the groove portion 30 reaches the main surface 8a of the base material 8.

[0022] As shown in FIG. 4(b), the width of the groove portion 30 in the X-axis direction, which is the width direction, is larger on the tip portion 13c side than on the bottom surface 30a side. The width of the groove portion 30 at the tip portion 13c is larger than the width of the groove portion 30 at the bottom surface 30a. In the example shown in FIG. 4(b), the groove portion 30 opens widely in the X-axis direction as it goes toward the tip portion 13c side. The pair of side surfaces 30b are inclined so that the distance between them increases as they go toward the positive side in the Z-axis direction.

[0023] Incidentally, the width of the groove portion 30 is not particularly limited as long as it is not excessively small for discharging the surplus structural member 20. For example, the width of the groove portion 30 may be 1 μm or more, and may be 4 μm or more. The wall frame portion 13 only needs to be large enough to position the electronic component 2, and the width of the groove portion 30 may be set larger.

[0024] As shown in FIG. 3, the wall 9 has an L-shaped frame body 40A (first frame body) and an L-shaped frame body 40B (second frame body). The frame bodies 40A and 40B are configured to be rotationally symmetric with respect to the central axis CL of the cavity 11. The central axis CL is set by an imaginary line extended in a direction orthogonal to the base material 8 with respect to the central position of the rectangular reference shape T1 described later (see also FIG. 2). Rotational symmetry means a relationship in which one shape coincides with the other shape when the one shape is rotated 180° around the central axis CL. The frame bodies 40A and 40B are formed by dividing the rotationally symmetric rectangular annular wall 9 with respect to the central axis CL by a pair of groove portions 30A and 30B. Therefore, the groove portions 30A and 30B are also configured to be rotationally symmetric with respect to the central axis CL.

[0025] The groove portion 30A formed in the wall frame portion 13C is formed on the positive side in the X-axis direction with respect to the central axis CL. The side surface 30b on the positive side in the X-axis direction of the groove portion 30A is arranged at the same position in the X-axis direction and extends in the Y-axis direction so as to be a continuous surface with the inner peripheral surface 13Aa of the wall frame portion 13A. The side surface 30b on the negative side in the X-axis direction of the groove portion 30A is arranged at a position separated from the inner peripheral surface 13Aa to the negative side in the X-axis direction. In FIG. 3, the side surface 30b on the negative side in the X-axis direction of the groove portion 30A is arranged at a position on the positive side in the X-axis direction with respect to the central axis CL in the X-axis direction, but it may be arranged at the same position as the central axis CL or at a position on the negative side in the X-axis direction.

[0026] The groove portion 30B formed in the wall frame portion 13D is formed on the negative side in the X-axis direction with respect to the central axis CL. The side surface 30b on the negative side in the X-axis direction of the groove portion 30B is arranged at the same position in the X-axis direction and extends in the Y-axis direction so as to be a surface continuous with the inner peripheral surface 13Ba of the wall frame portion 13B. The side surface 30b on the positive side in the X-axis direction of the groove portion 30B is arranged at a position separated from the inner peripheral surface 13Ba toward the positive side in the X-axis direction. In FIG. 3, the side surface 30b on the positive side in the X-axis direction of the groove portion 30B is arranged at a position on the negative side in the X-axis direction with respect to the central axis CL in the X-axis direction, but it may be arranged at the same position as the central axis CL or at a position on the positive side in the X-axis direction.

[0027] The frame body 40A has a first side portion 41A extending in the Y-axis direction and a second side portion 42A extending in the X-axis direction. The first side portion 41A is constituted by the wall frame portion 13A and a part of the wall frame portion 13C. A part of the wall frame portion 13C is a portion on the positive side in the X-axis direction of the wall frame portion 13C with respect to the groove portion 30A. The second side portion 42A is constituted by a part of the wall frame portion 13D. A part of the wall frame portion 13D is a portion on the positive side in the X-axis direction of the wall frame portion 13D with respect to the groove portion 30B.

[0028] The frame body 40B has a first side portion 41B extending in the Y-axis direction and a second side portion 42B extending in the X-axis direction. The first side portion 41B is constituted by the wall frame portion 13B and a part of the wall frame portion 13D. A part of the wall frame portion 13D is a portion on the negative side in the X-axis direction of the wall frame portion 13D with respect to the groove portion 30B. The second side portion 42B is constituted by a part of the wall frame portion 13C. A part of the wall frame portion 13C is a portion on the negative side in the X-axis direction of the wall frame portion 13C with respect to the groove portion 30A.

[0029] Here, a rectangular annular reference shape T1 is set for the cavity 11. The reference shape T1 is a virtual shape having the minimum area circumscribing the inner peripheral surface 13a of the wall 9 when viewed from the height direction (Z-axis direction). The reference shape T1 is shown by a one-dot chain line in FIG. 3. In the present embodiment, the reference shape T1 has a rectangular shape with the X-axis direction as the longitudinal direction.

[0030] The reference shape T1 has a pair of long side portions Sc and Sd extending in the X-axis direction, which is the longitudinal direction. The pair of long side portions Sc and Sd are spaced apart from each other in the Y-axis direction. The long side portion Sc on the positive side in the Y-axis direction has a line segment depicted by a part of the inner peripheral surface 13Ca of the wall frame portion 13C and a virtual extension line of the inner peripheral surface 13Ca, which is a line segment crossing the groove portion 30A in the X-axis direction. The long side portion Sd on the negative side in the Y-axis direction has a line segment depicted by a part of the inner peripheral surface 13Da of the wall frame portion 13D and a virtual extension line of the inner peripheral surface 13Da, which is a line segment crossing the groove portion 30B in the X-axis direction.

[0031] The reference shape T1 has a pair of short side portions Sa and Sb extending in the Y-axis direction, which is the short side direction. The pair of short side portions Sa and Sb are spaced apart from each other in the X-axis direction. The short side portion Sa on the positive side in the X-axis direction has a line segment depicted by the inner peripheral surface 13Aa of the wall frame portion 13A. The short side portion Sb on the negative side in the X-axis direction has a line segment depicted by the inner peripheral surface 13Ba of the wall frame portion 13B.

[0032] The electronic component 2 (shown by phantom lines) disposed in the cavity 11 is positioned by a pair of frame bodies 40A and 40B. The frame bodies 40A and 40B position the electronic component 2 using the respective inner peripheral surfaces 13Aa, 13Ba, 13Ca, and 13Da as regulating surfaces. Therefore, the electronic component 2 inserted into the cavity 11 is automatically positioned by the respective inner peripheral surfaces 13Aa, 13Ba, 13Ca, and 13Da and is arranged to fit within the range of the reference shape T1. That is, the electronic component 2 is positioned so as not to protrude outward from the reference shape T1. When the central axis of the electronic component 2 is accurately arranged to coincide with the central axis CL of the cavity 11, the gap between the outer peripheral surface of the electronic component 2 and each of the inner peripheral surfaces 13Aa, 13Ba, 13Ca, and 13Da of the wall 9 is set to about 0 μm to 5.0 μm. If the gap is too large, the positioning accuracy decreases, and if the gap is too small, it becomes difficult to insert the electronic component 2 into the cavity 11. By setting the gap within the above range, positioning can be performed easily and accurately.

[0033] With respect to the frame bodies 40A and 40B and the cavity 11 as described above, a pair of terminals 10 are formed on the main surface 8a of the base material 8. The pair of terminals 10 have a configuration that is rotationally symmetric about the central axis CL. The pair of terminals 10 have a portion arranged on the outer peripheral side from the reference shape T1. The terminal 10A (the first terminal) is arranged on the positive side in the X-axis direction with respect to the central axis CL. The terminal 10A extends in the positive Y-axis direction from the position where the terminal 7 of the electronic component 2 is arranged within the reference shape T1. The terminal 10A extends to the outer peripheral side (the positive side in the Y-axis direction) from the long side portion Sc of the reference shape T1 and is arranged within the groove portion 30A. In the groove portion 30A, the terminal 10A is formed on the main surface 8a of the base material 8 (see FIG. 4) that constitutes the bottom surface 30a of the groove portion 30A. In the groove portion 30A, the terminal 10A extends to the position of the outer peripheral surface 13Cb, but the position to which it extends with respect to the groove portion 30A is not particularly limited. In the present embodiment, the terminal 10A has a portion arranged on the outer peripheral side only from one long side portion Sc (the long side portion on the positive side in the Y-axis direction) of the rectangular reference shape T1.

[0034] The terminal 10B (the second terminal) is arranged on the negative side in the X-axis direction with respect to the central axis CL. The terminal 10B extends in the negative Y-axis direction from the position where the terminal 7 of the electronic component 2 is arranged within the reference shape T1. The terminal 10B extends to the outer peripheral side (the negative side in the Y-axis direction) from the long side portion Sd of the reference shape T1 and is arranged within the groove portion 30B. In the groove portion 30B, the terminal 10B is formed on the main surface 8a of the base material 8 (see FIG. 4) that constitutes the bottom surface 30a of the groove portion 30B. In the groove portion 30B, the terminal 10B extends to the position of the outer peripheral surface 13Db, but the position to which it extends with respect to the groove portion 30B is not particularly limited. In the present embodiment, the terminal 10B has a portion arranged on the outer peripheral side only from one long side portion Sd (the long side portion on the negative side in the Y-axis direction) of the rectangular reference shape T1.

[0035] The minimum opening dimension A of the groove portions 30A and 30B is equal to or less than the dimension B of the short side of the electronic component 2 that can be mounted on the terminals 10A and 10B. In the present embodiment, the groove portions 30A and 30B extend in the Y-axis direction with a constant width from the inner peripheral surfaces 13Ca and 13Da and open at the outer peripheral surfaces 13Cb and 13Db. Therefore, the width dimension itself of the groove portions 30A and 30B becomes the minimum opening dimension A of the groove portions 30A and 30B.

[0036] With reference to FIGS. 5 and 6, a method for manufacturing the circuit board 3 and the mounting board 1 will be described. First, as shown in FIG. 5(a), terminals 10 are formed on the upper surface of the base material 8. Next, as shown in FIG. 5(b), a wall 9 is formed on the base material 8. Thereby, the circuit board 3 is completed. In FIG. 5(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. 5(c), by filling the cavity 11 with the constituent material 20, the constituent material 20 is arranged on the base material 8. Then, the electronic component 2 is held by the holding member and the electronic component 2 is mounted in the cavity 11. Next, as shown in FIG. 6, the electronic component 2 is pushed into the cavity 11 by the pressure reflow device 49 with respect to the electronic component 2, and the bonding material 4A and the bonding material 4B are brought into contact with each other inside the constituent material 20. At this time, a part of the constituent material 20 is pushed out into the groove portion 30 (see FIG. 3). Next, by heating, the bonding material 4B of the electronic component 2 and the bonding material 4A of the base material 8 are bonded to each other. Thereby, the mounting board 1 is completed. In this process, the electronic component 2 is positioned within the cavity 11 by the frame bodies 40A and 40B (see FIG. 3).

[0037] Next, with reference to FIG. 7, a method for forming the wall 9 having the groove portion 30 will be described. First, as shown in FIG. 7(a), a wall 9 is formed on the base material 8. Next, as shown in FIG. 7(b), a part of the wall 9 is processed by irradiating the wall 9 with a laser using a laser device 51. Thereby, as shown in FIG. 7(c), the groove portion 30 is formed in the wall 9.

[0038] Alternatively, as shown in FIG. 7(d), a resist 52 is formed on the base material 8. Next, as shown in FIG. 7(e), exposure is performed using a glass mask 53 having a pattern corresponding to the shape of the wall 9 having the groove portion 30. As shown in FIG. 7(f), by developing the exposed resist 52, the wall 9 having the groove portion 30 is formed.

[0039] Next, the operations and effects of the manufacturing method of the circuit board 3 and the mounting board 1 according to the present embodiment will be described.

[0040] First, a circuit board 103 according to a comparative example will be described with reference to FIGS. 8 and 9. As shown in FIG. 8, the wall 9 of the circuit board 103 does not have the groove portion 30 described above. When the electronic component 2 is miniaturized, the cavity 11 is also miniaturized accordingly. At this time, since the terminal 10 has to be arranged within the range surrounded by the inner peripheral surface 13a of the wall 9, it is necessary to make the terminal 10 in the cavity 11 smaller. However, forming a small-sized pattern is difficult to form with high positional accuracy due to problems such as the resolution limit of the resist and the exposure apparatus, and there are problems such as a decrease in yield due to a decrease in quality caused by dimensional variations. Also, for example, when the wall 9 and the terminal 10 are overlapped, a defect occurs in the formation pattern of the terminal 10. When the wall 9 and the terminal 10 cannot be overlapped in this way, a gap GP between the inner peripheral surface 13a and the terminal 10 must be provided with dimensions considering the alignment accuracy and dimensional variations of the exposure apparatus. In this case, the cavity 11 becomes large, and the positioning accuracy of the electronic component 2 decreases.

[0041] Also, as shown in FIG. 9, after filling the inside of the wall 9 with the constituent material 20 and mounting the electronic component 2 in the wall 9 using a holding member, when trying to push the electronic component 2 with a pressure reflow apparatus, due to the influence of the excess constituent material 20, the electronic component 2 cannot be pushed in sufficiently. In this case, reflow may be performed with the bonding material 4B of the electronic component 2 and the bonding material 4A of the circuit board 3 remaining separated, and there is a possibility of a connection failure between the bonding material 4A of the circuit board 3 and the electronic component 2.

[0042] In contrast, in the circuit board 3 according to the present embodiment, the terminal 10A (first terminal) and the terminal 10B (second terminal) are arranged in the cavity 11. Therefore, when mounting the electronic component 2 on the circuit board 3, the electronic component 2 is inserted into the cavity 11 and joined to the terminals 10A and 10B via the bonding material 4A. At this time, the electronic component 2 is positioned by the inner peripheral surface 13a of the wall 9. Therefore, when reducing the size of the electronic component 2, by reducing the size of the cavity 11 as well, accurate positioning of the electronic component 2 becomes possible. When a reference shape T1 in the form of a rectangular shape with the minimum area circumscribing the inner peripheral surface 13a of the wall 9 is set as viewed from the Z-axis direction (first direction), if the terminals 10A and 10B are to be accommodated within the range of the reference shape T1, as described above, it becomes necessary to reduce the terminals 10A and 10B as the cavity 11 is miniaturized. In contrast, in the circuit board 3 according to the present embodiment, at least one groove portion 30 penetrating from the inner peripheral surface 13a to the outer peripheral surface 13b is formed in the wall 9. Thus, by providing the groove portion 30 in the wall 9, the groove portion 30 can be secured as a space for arranging the terminals 10A and 10B. At least one of the terminals 10A and 10B has a portion arranged on the outer peripheral side from the reference shape T1 via the groove portion 30. Therefore, by also utilizing the space on the outer peripheral side of the reference shape T1, it is possible to suppress at least one of the terminals 10A and 10B from becoming excessively small. Thereby, the difficulty of pattern formation of the terminals 10A and 10B can be reduced and the quality can be stabilized. From the above, it is possible to suppress a decrease in quality and accurately position the electronic component 2.

[0043] Also, the wall 9 has at least one groove portion 30 penetrating from the inner peripheral surface 13a to the outer peripheral surface 13b. In this case, when the electronic component 2 is mounted on the circuit board 3 by arranging the constituent material 20 in the cavity 11, mounting the electronic component 2 using a holding member, and pushing and heating the electronic component 2 into the interior of the cavity 11 using a pressure reflow device and joining it to the circuit board 3, the excess constituent material 20 can be discharged to the outside of the wall 9 via the groove portion 30. Thereby, in the pressurizing process using the pressure reflow device, the electronic component 2 can be sufficiently pushed into the cavity 11 and brought into contact with the bonding material 4.

[0044] The wall 9 has an L-shaped frame body 40A (first frame body) and an L-shaped frame body 40B (second frame body), and the frame bodies 40A and 40B may be configured to be rotationally symmetric with respect to the central axis CL of the cavity 11. In this case, by using the rotationally symmetric L-shaped frame bodies 40A and 40B, the electronic component 2 can be positioned well-balanced from all four directions. Further, as shown in FIG. 10(a), in 103 according to the comparative example, with the cavity 11 being large with respect to the electronic component 2, the inner peripheral surface 13a surrounds the entire circumference. In this case, when a plurality of electronic components 2 are positioned in each cavity 11, each electronic component 2 will have a displacement in a non-uniform direction. On the other hand, in the circuit board 3 according to the present embodiment, by using the rotationally symmetric frame bodies 40A and 40B, even if a displacement of the electronic component 2 occurs within the cavity 11, the rotational direction of the displacement can be made uniform. In this case, when the electronic component 2 emits light, compared with the case of being displaced non-uniformly as in the comparative example, the non-uniformity of the overall light emission position can be suppressed. Also, by making the direction of the displacement uniform, it becomes easier to detect defective products in the inspection.

[0045] The minimum opening dimension A of the groove portion 30 may be equal to or less than the dimension B of the short side of the electronic component 2 that can be mounted on the terminals 10A and 10B. In this case, even if rotation or displacement of the electronic component 2 occurs within the cavity 11, movement from the groove portion 30 to the outer peripheral side can be suppressed, and it can be kept within the cavity 11.

[0046] At least one of the terminals 10A and 10B may have a portion disposed on the outer peripheral side from only one side portion of the rectangular reference shape T1. In this case, the size of the groove portion 30 can be reduced, and rotation and displacement of the electronic component 2 within the cavity 11 can be suppressed.

[0047] 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.

[0048] The manufacturing method of the mounting substrate 1 according to this embodiment is a manufacturing method of the mounting substrate 1 for manufacturing the mounting substrate 1 by mounting the electronic component 2 on the above-described circuit board 3. The manufacturing method may be to arrange the structural member 20 on the base material 8, arrange the electronic component 2, and then join the electronic component 2 to the terminal 10 using the pressure reflow device 49.

[0049] In this case, the above-described circuit board 3 can obtain the same functions and effects.

[0050] This disclosure is not limited to the above-described embodiments. For example, the number and arrangement of the terminals of the circuit board are not particularly limited.

[0051] The structure of the wall 9 is not limited to the above-described embodiments. For example, the structure shown in FIG. 11 may be adopted. The circuit board 3 shown in FIG. 11 has a groove portion 30 extending in the X-axis direction, and the terminals 10A and 10B extend in the X-axis direction. In the example of FIG. 11, the groove portion 30A extends to the positive side in the X-axis direction so as to form a side surface 30b continuous with the inner peripheral surface 13Ca in the wall frame portion 13A. The groove portion 30B extends to the negative side in the X-axis direction so as to form a side surface 30b continuous with the inner peripheral surface 13Da in the wall frame portion 13B. Thereby, the frame body 40A has a first side portion 41A extending in a short range in the Y-axis direction on the positive side in the X-axis direction and a second side portion 42A extending long in the X-axis direction on the negative side in the Y-axis direction. The frame body 40B has a first side portion 41B extending in a short range in the Y-axis direction on the negative side in the X-axis direction and a second side portion 42B extending long in the X-axis direction on the positive side in the Y-axis direction.

[0052] The terminal 10A extends to the outer peripheral side (the positive side in the X-axis direction) from the short side portion Sa of the reference shape T1 and is disposed in the groove portion 30A. The terminal 10A has a portion disposed to the outer peripheral side only from one short side portion Sa (the short side portion on the positive side in the X-axis direction) of the rectangular reference shape T1. The terminal 10B extends to the outer peripheral side (the negative side in the X-axis direction) from the short side portion Sb of the reference shape T1 and is disposed in the groove portion 30B. The terminal 10B has a portion disposed to the outer peripheral side only from one short side portion Sb (the short side portion on the negative side in the X-axis direction) of the rectangular reference shape T1.

[0053] For example, the structure shown in FIG. 12 may be adopted. The circuit board 3 shown in FIG. 12 has a large groove portion 30A at the corner between the wall frame portions 13A and 13C, and a large groove portion 30B at the corner between the wall frame portions 13B and 13D. The side surface 30b on the wall frame portion 13A side of the groove portion 30A extends in the X-axis direction at a position on the negative side in the Y-axis direction with respect to the central axis CL. The side surface 30b on the wall frame portion 13C side of the groove portion 30A extends in the Y-axis direction at a position on the positive side in the X-axis direction with respect to the central axis CL. The side surface 30b on the wall frame portion 13B side of the groove portion 30B extends in the X-axis direction at a position on the positive side in the Y-axis direction with respect to the central axis CL. The side surface 30b on the wall frame portion 13D side of the groove portion 30B extends in the Y-axis direction at a position on the negative side in the X-axis direction with respect to the central axis CL. Thereby, the frame body 40A has a first side portion 41A that extends in a short range in the Y-axis direction on the positive side in the X-axis direction, and a second side portion 42A that extends in the X-axis direction on the negative side in the Y-axis direction. The frame body 40B has a first side portion 41B that extends in a short range in the Y-axis direction on the negative side in the X-axis direction, and a second side portion 42B that extends in the X-axis direction on the positive side in the Y-axis direction.

[0054] The terminal 10A extends to the outer peripheral side (the positive side in the Y-axis direction) from the long side portion Sc of the reference shape T1 and is disposed in the groove portion 30A. The terminal 10A has a portion disposed on the outer peripheral side only from one long side portion Sc (the long side portion on the positive side in the Y-axis direction) of the rectangular reference shape T1. The terminal 10B extends to the outer peripheral side (the negative side in the Y-axis direction) from the long side portion Sd of the reference shape T1 and is disposed in the groove portion 30B. The terminal 10B has a portion disposed on the outer peripheral side only from one long side portion Sd (the long side portion on the negative side in the Y-axis direction) of the rectangular reference shape T1.

[0055] Note that, as in the example shown in FIG. 12, the minimum opening dimension A of the groove portion 30 may be larger than the short side dimension B of the electronic component 2. However, the opening dimension A may be made equal to or smaller than the short side dimension B by making the groove portion 30 smaller.

[0056] The structure shown in FIG. 13 may be adopted. The circuit board 3 shown in FIG. 13 has wider terminals 10A and 10B than those in FIG. 12. Terminal 10A extends to the outer peripheral side (the positive side in the Y-axis direction) from the long side portion Sc of the reference shape T1, extends to the outer peripheral side (the positive side in the X-axis direction) from the short side portion Sa, and is disposed in the groove portion 30A. Terminal 10B extends to the outer peripheral side (the negative side in the Y-axis direction) from the long side portion Sd of the reference shape T1, extends to the outer peripheral side (the negative side in the X-axis direction) from the short side portion Sb, and is disposed in the groove portion 30B. Thus, terminals 10A and 10B may have portions disposed on the outer peripheral side from the reference shape T1 in a plurality of directions.

[0057] Also, the structure shown in FIG. 14 may be adopted. In the circuit board 3 shown in FIG. 14, the wall 9 is formed with groove portions 30A and 30B (first groove portions) in which terminals 10A and 10B are disposed and groove portions 30C and 30D (second groove portions) in which terminals 10A and 10B are not disposed as groove portions 30. In this case, when excess structural material 20 is generated by pushing the electronic component 2 into the cavity 11, it can be discharged to the outside of the cavity through the groove portions 30C and 30D. In FIG. 14, a narrow groove portion 30C is formed at the corner between the wall frame portions 13A and 13D, and a narrow groove portion 30D is formed at the corner between the wall frame portions 13B and 13C with respect to the wall 9 shown in FIG. 13.

[0058] Also, the structure shown in FIG. 15 may be adopted. The circuit board 3 shown in FIG. 15 is formed with a narrow groove portion 30E extending in the Y-axis direction in the wall frame portion 13D and a narrow groove portion 30F extending in the Y-axis direction in the wall frame portion 13C with respect to the wall 9 shown in FIG. 14.

[0059] In the above-described embodiments and modifications, both the terminal 10A (first terminal) and the terminal 10B (second terminal) had portions disposed on the outer peripheral side from the reference shape through the groove portions. However, it is sufficient that at least one of the terminals 10A (first terminal) and 10B (second terminal) has a portion disposed on the outer peripheral side from the reference shape through the groove portion, and the other terminal does not have to have a portion disposed on the outer peripheral side from the reference shape.

[0060] [Embodiment 1] A base material having a main surface, a first terminal and a second terminal provided on the main surface of the base material, and a wall of an insulating material provided on the main surface of the base material, which is a circuit board comprising: the wall has at least one groove portion penetrating from an inner peripheral surface to an outer peripheral surface, the first and second terminals are arranged in a cavity surrounded by the wall, and when setting a rectangular reference shape having a minimum area circumscribing the inner peripheral surface of the wall as viewed from a first direction orthogonal to the main surface of the base material, at least one of the first and second terminals has a portion arranged on the outer peripheral side from the reference shape through the groove portion, a circuit board. [Aspect 2] the wall has an L-shaped first frame body and an L-shaped second frame body, the first and second frame bodies are configured to be rotationally symmetric with respect to a central axis of the cavity, the circuit board described in Aspect 1. [Aspect 3] the minimum opening dimension of the groove portion is equal to or less than the dimension of the short side of an electronic component that can be mounted on the first and second terminals, the circuit board described in Aspect 1 or 2. [Aspect 4] at least one of the terminals has a portion arranged on the outer peripheral side only from one side portion of the rectangular reference shape, the circuit board described in any one of Aspects 1 to 3. [Aspect 5] the wall has, as the groove portion, a first groove portion where at least one of the terminals is arranged and a second groove portion where at least one of the terminals is not arranged, the circuit board described in any one of Aspects 1 to 4. [Aspect 6] a first bonding material containing a metal element arranged on the first terminal and a second bonding material containing a metal element arranged on the second terminal, the circuit board described in any one of Aspects 1 to 5. [Aspect 7] A method for manufacturing a mounting board by mounting an electronic component on the circuit board according to any one of Aspects 1 to 6, A method for manufacturing a mounting substrate, comprising arranging a structural member on the base material, arranging the electronic component, and then joining the electronic component to the first and second terminals using a pressure reflow device.

Explanation of Signs

[0061] 1... mounting substrate, 2... electronic component, 3... circuit board, 4A... bonding material, 8... base material, 9... wall, 10A... terminal (first terminal), 10B... terminal (second terminal), 30... groove portion, 30A, 30B... groove portion (first groove portion), 30C, 30D, 30E, 30F... groove portion (second groove portion), 40A... frame body (first frame body), 40B... frame body (second frame body), 49... pressure reflow device.

Claims

1. a substrate having a main surface; a first terminal and a second terminal provided on the main surface of the substrate; a wall of an insulating material provided on the main surface of the substrate, a circuit board comprising: the wall has at least one groove penetrating from an inner peripheral surface to an outer peripheral surface; the first and second terminals are disposed in a cavity surrounded by the wall, and when a rectangular reference shape having a minimum area circumscribing the inner peripheral surface of the wall is set when viewed from a first direction orthogonal to the main surface of the substrate, at least one of the first and second terminals has a portion disposed on the outer peripheral side from the reference shape through the groove, a circuit board.

2. the wall has an L-shaped first frame and an L-shaped second frame; the first and second frames are configured to be rotationally symmetric with respect to a central axis of the cavity, the circuit board according to claim 1.

3. the minimum opening dimension of the groove is equal to or less than the dimension of the short side of an electronic component that can be mounted on the first and second terminals, the circuit board according to claim 1.

4. at least one of the terminals has a portion disposed on the outer peripheral side from only one side portion of the rectangular reference shape, the circuit board according to claim 1.

5. the wall has, as the groove, a first groove in which at least one of the terminals is disposed and a second groove in which at least one of the terminals is not disposed, the circuit board according to claim 1.

6. a first bonding material containing a metal element disposed on the first terminal and a second bonding material containing a metal element disposed on the second terminal, the circuit board according to claim 1.

7. a method for manufacturing a mounting substrate by mounting an electronic component on the circuit board according to any one of claims 1 to 6, the method for manufacturing a mounting substrate comprising: arranging a constituent material on the substrate, arranging the electronic component, and then joining the electronic component to the first and second terminals using a pressure reflow device, a method for manufacturing a mounting substrate.

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