Method for manufacturing printed circuit board with electronic component, and printed circuit board with electronic component

Abstract

To provide a method for manufacturing a printed circuit board with an electronic component and a printed circuit board with an electronic component, the electronic component having a structure in which it is easier to apply a coating resin of a desired thickness and within a desired range.SOLUTION: A method for manufacturing a printed circuit board with an electronic component is a method for manufacturing a printed circuit board with an electronic component 100, the printed circuit including a substrate 10, an electronic component 30, and a coating resin 20 covering the electronic component 30, and the method performs a mounting step and a coating step in this order. The coating step includes a first coating step of coating the electronic component 30 with the coating resin 20, a first curing step of curing the coating resin 20 coated in the first coating step, a second coating step of coating the coating resin 20 by laminating the coating resin 20 on the coating resin 20 cured in the first curing step, and a second curing step of curing the coating resin 20 coated in the second coating step.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a printed circuit board with electronic components, and a printed circuit board with electronic components.

Background Art

[0002] The method for manufacturing a printed circuit board with electronic components (described as a printed circuit board in the same document) described in Patent Document 1 includes an insulating base material (described as a base film in the same document), electronic components mounted on the base material, and an insulating coating resin that covers at least a part of the electronic components (described as a protective film in the same document), an insulating layer laminated in a non-mounting area of the electronic components on the base material, and a concave groove formed on the surface of the insulating layer. The method for manufacturing a printed circuit board with electronic components includes a coating step of covering at least a part of the electronic components with the coating resin, and the flow-out of the coating resin before curing is restricted by the concave groove.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the study of the inventor of the present application, the method for manufacturing a printed circuit board with electronic components in Patent Document 1 has room for improvement from the viewpoint of more easily forming the coating resin within a desired thickness and range.

[0005] The present invention has been made in view of the above problems, and relates to a method for manufacturing a printed circuit board with electronic components having a structure that makes it easier to form a coating resin within a desired thickness and range, and a printed circuit board with electronic components.

Means for Solving the Problems

[0006] According to the present invention, there is provided a method for manufacturing a printed circuit board with electronic components, comprising an insulating base material, electronic components mounted on the base material, and an insulating coating resin covering at least a part of the electronic components, a mounting step of mounting the electronic components on the base material, a coating step of coating at least a part of the electronic components with the coating resin, which are performed in this order, wherein the coating step includes a first coating step of applying the coating resin to at least a part of the electronic components, a first curing step of curing the coating resin applied in the first coating step, a second coating step of applying the coating resin by laminating it on the coating resin cured in the first curing step, and a second curing step of curing the coating resin applied in the second coating step. A method for manufacturing a printed circuit board with electronic components is provided. See In the second coating step, the range where the coating resin is applied is a region inside the outer contour line of the coating resin cured in the first curing step in a plan view, and the coating resin is applied so that a step is formed at the boundary between the coating resin cured in the first coating step and the coating resin to be applied in the second coating step According to the present invention, there is provided an insulating base material,

[0007] electronic components mounted on the base material, and an insulating coating resin covering the electronic components, wherein the coating resin has a main part covering at least a part of the electronic components and a sub part disposed around the main part, and a printed circuit board with electronic components is provided, in which the film thickness of the main part is thicker than the film thickness of the sub part, and a step exists at the boundary between the main part and the sub part. The film thickness of the main part is thicker than that of the sub part, and a step exists at the boundary between the main part and the sub part. A printed circuit board with electronic components is provided.

Advantages of the Invention

[0008] According to the present invention, it becomes easier to form the coating resin within a desired thickness and range.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

[0011] 〔First Embodiment〕 First, the first embodiment will be described with reference to FIGS. 1(a) to 3(c).

[0012] As shown in FIGS. 1(a) to 3(c), a method for manufacturing a printed circuit board with electronic components according to this embodiment (hereinafter sometimes referred to as this method) is a method for manufacturing a printed circuit board 100 with electronic components, which includes an insulating base material 10, electronic components 30 mounted on the base material 10, and an insulating coating resin 20 covering at least a part of the electronic components 30. In this method, a mounting step of mounting the electronic components 30 on the base material 10 and a coating step of covering at least a part of the electronic components 30 with the coating resin 20 are performed in this order. The coating step includes a first coating step of applying the coating resin 20 to at least a part of the electronic components 30, a first curing step of curing the coating resin 20 applied in the first coating step, a second coating step of applying the coating resin 20 by laminating it on the coating resin 20 cured in the first curing step, and a second curing step of curing the coating resin 20 applied in the second coating step.

[0013] In the printed circuit board 100 with electronic components, from the viewpoint of protecting the electronic components 30 from dust, moisture, physical impact, etc., it is preferable that the film thickness of the coating resin 20 is thick. Here, the resin material used as the coating resin 20 has the characteristic that the wetting spreadability (fluidity) with respect to the cured coating resin 20 is lower than the wetting spreadability (fluidity) with respect to the material constituting the base material 10. And according to this method, in the second coating step, since the coating resin 20 is further applied and laminated on the coating resin 20 cured in the first curing step, it is possible to suppress the coating resin 20 applied in the second coating step from spreading widely on the surface of the coating resin 20 cured in the first curing step. Thereby, the film thickness of the coating resin 20 can be easily increased. Furthermore, since the coating resin 20 applied in the second coating step can ensure a sufficient film thickness of the coating resin 20, the amount of the coating resin 20 applied in the first coating step can be made smaller. As a result, the formation range of the coating resin 20 can be minimized. Thus, according to this method, it becomes easier to form the coating resin 20 within a desired thickness and range. Also, according to this method, even if a low-viscosity coating resin 20 that is less expensive than the high-viscosity coating resin 20 is used, the film thickness of the coating resin 20 can be easily increased, so that the material cost can be further suppressed. Furthermore, according to the present invention, by adjusting the amount of the coating resin 20 to be applied without using a dedicated jig for restricting the formation range of the coating resin 20, the coating resin 20 can be thickly applied within a desired range. Therefore, since it is not necessary to consider the shape and dimensions of the jig, the shape and dimensions of the printed circuit board 100 with electronic components can be set with a higher degree of freedom.

[0014] Hereinafter, an example of the structure of the printed circuit board 100 with electronic components manufactured according to the present embodiment will be described with reference to FIGS. 1(a) and 1(b). In the following, when explaining the positional relationship between the components of the printed circuit board 100, the upper side in FIG. 1(b) is referred to as the upper side or the upper direction, and the opposite side is referred to as the lower side or the lower direction. However, these direction definitions are for convenience and do not limit the direction during the manufacturing or use of the printed circuit board 100 with electronic components.

[0015] The printed circuit board 100 with electronic components is used, for example, to monitor voltage by connecting the conductor pattern 40 to a bus bar (not shown) that connects a plurality of battery cells (not shown) incorporated in a voltage monitoring module (not shown). More specifically, the printed circuit board 100 with electronic components has, for example, a connector (not shown) attached thereto, and is connected via the connector to a measuring device that performs various controls, enabling voltage monitoring.

[0016] The printed circuit board 100 with electronic components is a laminate formed flat. The planar shape of the printed circuit board 100 with electronic components is not particularly limited, but as an example, it can be substantially rectangular (for example, a rectangular shape with rounded corners). Note that the printed circuit board 100 with electronic components may be a flexible printed circuit board (flexible board) or a rigid board.

[0017] As described above, the printed circuit board 100 with electronic components according to the present embodiment includes an insulating base material 10, electronic components 30 mounted on the base material 10, and an insulating coating resin 20 that covers at least a part of the electronic components 30.

[0018] The base material 10 is, for example, a relatively thin base material with the front and back being the main surfaces. More specifically, when the printed circuit board 100 with electronic components is a flexible printed circuit board, the base material 10 is, for example, formed in a film shape, and when the printed circuit board 100 with electronic components is a rigid board, the base material 10 is, for example, formed in a flat plate shape. The base material 10 is composed of an insulating and thermoplastic resin material, and in this embodiment, it is composed of polyimide. However, the material of the base material 10 is not limited to this example, and for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), liquid crystal polymer (LCP), fluororesin (PTFE), or a resin material containing them may be used.

[0019] In the case of this embodiment, the electronic component 30 is a rectangular surface mount component, and the electronic component 30 is surface-mounted on one surface 10a of the base material 10. More specifically, a conductor pattern 40 (see FIG. 1(b)) is formed on one surface 10a of the base material 10, and the conductor pattern 40 is electrically connected to the electronic component 30. Note that in FIG. 1(a), the illustration of the conductor pattern 40 is omitted. The conductor pattern 40 is formed by processing a copper foil. An electronic component 30 is mounted on one end portion in the extending direction of the conductor pattern 40. The electronic component 30 is joined to one end portion of the conductor pattern 40 by, for example, solder (not shown) and is electrically connected to the conductor pattern 40. The rectangular surface mount component is not particularly limited, and examples thereof include a semiconductor chip, a ceramic capacitor, a resistor, and the like.

[0020] The coating resin 20 is not particularly limited, and examples thereof include acrylic, silicone, phenol, epoxy, and the like. Further, as the coating resin 20, for example, it is also preferable to use an ultraviolet curable resin material, and it is particularly preferable to use an ultraviolet curable resin material mainly composed of epoxy and containing a photo-crosslinking agent. When using an ultraviolet curable resin material, the coating resin 20 can be cured by ultraviolet irradiation. However, the coating resin 20 is not limited to ultraviolet curable type, and may be, for example, heat curable type or solvent vaporization type.

[0021] In the case of this embodiment, as shown in FIGS. 1(a) and 1(b), the coating resin 20 covers the entire electronic component 30. Thereby, the coating resin 20 can more reliably protect the electronic component 30 from dust, moisture, physical impact, and the like. More specifically, the coating resin 20 covers the entire surface of the electronic component 30 that is exposed from the base material 10, and does not cover the surface (one surface 30a) of the electronic component 30 that faces one surface 10a of the base material 10. Also, in a plan view, the entire outer contour line of the electronic component 30 is disposed in a region, for example, inside the outer contour line of the coating resin 20. Also, a part of the coating resin 20 covers, for example, one surface 10a of the base material 10 and the upper surface of the conductor pattern 40.

[0022] As described above, the coating resin 20 is formed by applying and laminating the coating resin 20 again to the coating resin 20 cured in the first curing step in the second coating step. Therefore, the coating resin 20 has two layers, that is, the coating resin 20 applied in the first coating step and the coating resin 20 applied in the second coating step. More specifically, in the case of the present embodiment, the coating resin 20 has a main portion 23 covering at least a part of the electronic component 30 and a sub-portion 21 disposed around the main portion 23. The sub-portion 21 of the coating resin 20 is composed of one layer of the coating resin 20 applied in the first coating step, and the main portion 23 of the coating resin 20 is composed of two layers, that is, the coating resin 20 applied in the first coating step and the coating resin 20 applied in the second coating step. Therefore, the film thickness of the main portion 23 is thicker than the film thickness of the sub-portion 21. Note that "the film thickness of the main portion 23 is thicker than the film thickness of the sub-portion 21" means that at least the average value of the film thickness of the main portion 23 is larger than the average value of the film thickness of the sub-portion 21. Preferably, as shown in FIG. 1(b), the minimum film thickness (T3 shown in FIG. 1(b)) of the main portion 23 of the coating resin 20 is thicker than the maximum film thickness (T1 shown in FIG. 1(b)) of the sub-portion 21 of the coating resin 20.

[0023] Here, in the case of the present embodiment, a step 25 (see FIGS. 1(a) and 1(b)) exists at the boundary between the main portion 23 and the sub-portion 21. More specifically, the step 25 is the boundary between the coating resin 20 applied in the first coating step and the coating resin 20 applied in the second coating step. In the coating resin 20, the inside of the step 25 constitutes the main part 23, and the outside of the step 25 constitutes the sub part 21. Due to the presence of the step 25, it is possible to easily identify, based on the appearance of the printed circuit board 100 with electronic components, that the second coating step has been performed. In the case of this embodiment, in the coating resin 20, the maximum film thickness T1 of the sub part 21 is the maximum film thickness of the coating resin 20 applied in the first coating step, and the height of the step 25 (T2 shown in FIG. 1(b)) is the film thickness of the coating resin 20 applied in the second coating step. And the minimum film thickness T3 of the main part 23 is the combined thickness of the maximum film thickness of the coating resin 20 applied in the first coating step (the maximum film thickness T1 of the sub part 21) and the film thickness of the coating resin 20 applied in the second coating step (the height T2 of the step 25). In the present invention, the step 25 does not necessarily need to be present at the boundary between the sub part 21 and the main part 23 of the coating resin 20. For example, the boundary between the sub part 21 and the main part 23 may be such that the film thickness of the coating resin 20 gradually becomes thinner from the central part of the main part 23 toward the sub part 21.

[0024] Also, it is preferable that the height T2 of the step 25 is greater than the thickness of the sub part 21. By doing so, it becomes even easier to identify, based on the appearance of the printed circuit board 100 with electronic components, whether the second coating step has been performed. Note that "the height T2 of the step 25 is greater than the thickness of the sub part 21" means that the height T2 of the step 25 is thicker than at least the average value of the film thickness of the sub part 21 of the coating resin 20. In the case of this embodiment, the height T2 of the step 25 is greater than the maximum film thickness T1 of the sub part 21.

[0025] Furthermore, in the case of this embodiment, as shown in FIGS. 1(a) and 1(b), the entire outer contour line of the electronic component 30 is disposed in a region inside the outer contour line of the main portion 23 of the coating resin 20. That is, the electronic component 30 is entirely (except for one surface 30a) covered by the main portion 23 of the coating resin 20, which has a greater film thickness than the sub-portion 21. More specifically, the upper surface and the side peripheral surface of the electronic component 30 are covered by the main portion 23 of the coating resin 20. Thereby, the electronic component 30 can be better protected by the coating resin 20.

[0026] The minimum film thickness of the sub-portion 21 of the coating resin 20 is not particularly limited, but for example, it is preferably 10 μm or more. The minimum film thickness T3 of the main portion 23 of the coating resin 20 is not particularly limited, but for example, it is preferably 40 μm or more.

[0027] Hereinafter, with reference to FIGS. 2(a) to 3(c), the manufacturing method of the printed circuit board 100 with an electronic component according to this embodiment will be described in more detail. FIGS. 2(a) to 2(c) are cross-sectional views of the cut portions corresponding to FIG. 1(b).

[0028] As described above, in the manufacturing method of the printed circuit board 100 with an electronic component according to this embodiment, a mounting step of mounting the electronic component 30 on the base material 10 and a coating step of coating at least a part of the electronic component 30 with the coating resin 20 are performed in this order. First, in the mounting step, a base material 10 on which a conductor pattern 40 is formed is prepared. Then, as shown in FIGS. 2(a) and 3(a), an electronic component 30 (a rectangular surface mount component) is mounted on the upper surface of the conductor pattern 40, and the electronic component 30 is joined to the conductor pattern 40 by soldering. More specifically, terminals (not shown) are provided on the lower surface of the electronic component 30, and the terminals are joined to the land portions (not shown) of the conductor pattern 40. Next, in the coating process, as a first coating step, as shown in FIGS. 2(b) and 3(b), the coating resin 20 is applied over the entire surface (upper surface and side circumferential surface) excluding the lower surface of the electronic component 30, and on one surface 10a of the base material 10 and the portion located around the electronic component 30 in the conductor pattern 40 in a plan view. As described above, from the viewpoint of minimizing the formation range of the coating resin 20, the amount of the coating resin 20 applied here is preferably the minimum amount necessary to satisfactorily cover the electronic component 30. Then, as a first curing step, the coating resin 20 applied in the first coating step is cured. In the first curing step, the coating resin 20 may be semi-cured (before being completely crosslinked or polymerized) or fully cured (in a completely crosslinked or polymerized state, or in a completely dried state). Subsequently, as shown in FIGS. 2(c) and 3(c), as a second coating step, the coating resin 20 is applied by laminating it on the coating resin 20 cured in the first curing step. The amount of the coating resin 20 applied here is preferably less than that of the coating resin 20 applied in the first coating step. By doing so, it is possible to more surely suppress the coating resin 20 applied in the second coating step from spreading widely on the surface of the coating resin 20 cured in the first curing step and to be applied within a desired range. Therefore, while reducing the amount of the coating resin 20 applied in the second coating step, the film thickness of the coating resin 20 can be increased. Then, as a second curing step, the coating resin 20 applied in the second coating step is cured. In the second curing step, for example, only the coating resin 20 applied in the second coating step may be cured, or when the coating resin 20 applied in the first coating step is semi-cured, the coating resins 20 applied in the first coating step and the second coating step may be cured together completely. The method for applying the coating resin 20 is not particularly limited, and for example, a dipping method, a brush coating method, a spray method, a wire drawing coating method, a dispensing method, etc. can be used.

[0029] Here, in the case of this method, as shown in FIGS. 2(b), 2(c), 3(b) and 3(c), the range where the coating resin 20 is applied in the second coating step is, in a plan view, an area inside the outer contour line of the coating resin 20 cured in the first curing step. That is, in the second coating step, the coating resin 20 is applied in a range narrower than the formation range of the coating resin 20 cured in the first curing step. Thereby, since the entire coating resin 20 applied in the second coating step can be laminated on the coating resin 20 cured in the first curing step, the film thickness of the coating resin 20 can be increased over a wider range.

[0030] Furthermore, in the case of this method, in the covering step, the entire rectangular surface-mount component (electronic component 30) is covered with the coating resin 20. Note that the "entirety of the rectangular surface-mount component" as referred to here is the entire surface exposed from the base material 10 in the rectangular surface-mount component, excluding the surface (one surface 30a) facing one surface 10a of the base material 10 in the rectangular surface-mount component. Thereby, as described above, the rectangular surface-mount component (electronic component 30) can be more reliably protected from dust, moisture, physical impact, etc. by the coating resin 20. More specifically, in the case of this method, as an example, in the first coating step, the entire electronic component 30 is covered and the coating is applied such that the electronic component 30 is located at the center of the coating resin 20. Subsequently, in the second coating step, the coating resin 20 is applied to cover the entire electronic component 30 and is mainly located at the center of the coating resin 20 cured in the first curing step. Thereby, in the coating resin 20, a main part 23 and an auxiliary part 21 arranged around the main part 23 are formed, and a configuration in which the main part 23 covers the entire electronic component 30 can be realized. As shown in FIG. 3(c), in a plan view, the entire outer contour line of the rectangular surface-mount component is located in an area inside the outer contour line of the main part 23 of the coating resin 20.

[0031] In the present invention, in the coating process, for example, a coating process of applying the coating resin 20 to at least a part of the electronic component 30 and a curing process of curing the applied coating resin 20 may be repeatedly performed three or more times in this order. That is, for example, after the second coating process, as the third coating process, the coating resin 20 may be further laminated and applied to the coating resin 20 cured in the second curing process, and as the third curing process, the coating resin 20 may be cured. Further, in this case, in the first curing process and the second curing process, the coating resin 20 may be semi-cured, and in the third curing process, the coating resins 20 applied in the first to third coating processes may be collectively fully cured.

[0032] Also, in this method, as an example, the resin material of the coating resin 20 applied in the first coating process and the resin material of the coating resin 20 applied in the second coating process are resin materials of the same type as each other. However, in the present invention, the resin material of the coating resin 20 applied in the first coating process and the resin material of the coating resin 20 applied in the second coating process may be different resin materials from each other. In this case, the resin material of the coating resin 20 applied in the first coating process is preferably, for example, a resin material having high wettability (fluidity) with respect to the material constituting the base material 10. By doing so, the coating resin 20 can be thinly applied within a necessary range, so that the amount of the coating resin 20 used can be reduced. Also, the resin material of the coating resin 20 applied in the second coating process is preferably, for example, a resin material having low wettability (fluidity) with respect to the cured coating resin 20. By doing so, while the entire electronic component 30 can be well covered with the coating resin 20, the film thickness of the coating resin 20 can be increased.

[0033] 〔Second Embodiment〕 Next, the second embodiment will be described with reference to FIGS. 4(a) to 5(c). The printed circuit board 100 with electronic components according to this embodiment is different from the printed circuit board 100 with electronic components according to the first embodiment described above in the points described below, and is configured in the same manner as the printed circuit board 100 with electronic components according to the first embodiment in other points.

[0034] In the case of this embodiment, the electronic component 30 has lead terminals 36, and in the coating process, at least the lead terminals 36 are coated with the coating resin 20. Thereby, the coating resin 20 can preferably protect the lead terminals 36 from dust, moisture, physical impact, etc.

[0035] As shown in FIGS. 4(a) and 4(b), in the case of this embodiment, the electronic component 30 has, for example, a main body portion 35, and a plurality of lead terminals 36 are provided on the other surface 30b of the main body portion 35. The main body portion 35 is mounted on the surface (hereinafter, the other surface 10b) side opposite to the one surface 10a side of the base material 10. Each lead terminal 36 penetrates the base material 10 from the other surface 10b side toward the one surface 10a side.

[0036] As shown in FIG. 4(b), a plurality of through holes 15 are formed in the base material 10. Each through hole 15 penetrates the base material 10 in the thickness direction. Further, on one surface 10a of the base material 10, land portions 44 connected to the conductor patterns 40 are formed at portions corresponding to the respective through holes 15. Each land portion 44 is formed, for example, at the peripheral edge portion of the opening on the upper end side of the through hole 15 in the base material 10.

[0037] One lead terminal 36 is inserted into each through hole 15. In the example shown in FIG. 4(b), the lower end portion of the lead terminal 36 protrudes downward from the through hole 15, and the upper end portion of the lead terminal 36 protrudes upward from the through hole 15. That is, the upper end portion of each lead terminal 36 protrudes above one surface 10a of the base material 10. Here, also in the case of this embodiment, as will be described later, in the second coating step, the coating resin 20 cured in the first curing step is further coated and laminated with the coating resin 20. Therefore, the coating resin 20 can be well and thickly coated on each such lead terminal 36. Also, corresponding lead terminals 36 are joined to the land portions 44 of the respective through holes 15 via solder 50. Thereby, the electronic component 30 is mounted on the base material 10 and is electrically connected to the conductor pattern 40.

[0038] More specifically, the solder 50 is filled, for example, so as to fill the gap between the inner peripheral surface of each land portion 44 and the outer peripheral surface of the intermediate portion of the corresponding lead terminal 36. Also, a fillet 52 is formed along the entire outer periphery of the upper end portion of the lead terminal 36 and the entire upper end surface of the land portion 44. Note that a fillet (not shown) may be formed along the entire outer periphery of the lower end portion of the lead terminal 36. Also, depending on the amount of the solder 50, the fillet 52 may be selectively formed along a part of the outer periphery of the upper end surface or the lower end portion of the lead terminal 36, or the fillet 52 may not be substantially formed.

[0039] As shown in FIGS. 4(a) and 4(b), the coating resin 20 is formed, for example, on one surface 10a side of the base material 10 and covers the upper part of each lead terminal 36 and the entire fillet 52. Thereby, the coating resin 20 can satisfactorily protect each lead terminal 36 from dust, moisture, physical shock, and the like. In the case of this embodiment, as shown in FIG. 4( a ), in a plan view, the outer contour line of each lead terminal 36 and the outer contour line of the fillet 52 are arranged in a region inside the outer contour line of the coating resin 20. Note that the coating resin 20 may be formed so as to cover each lead terminal 36 and the fillet 52 in series, or may be formed in an island shape for each lead terminal 36 and the fillet 52.

[0040] Also, in the case of this embodiment as well, similar to the first embodiment, the film thickness in the main portion 23 is thicker than the film thickness in the sub-portion 21, and a step 25 exists at the boundary between the sub-portion 21 and the main portion 23 of the coating resin 20. As shown in FIG. 4(b), as an example, it is preferable that the minimum film thickness (T5 shown in FIG. 4(b)) in the main portion 23 is thicker than the maximum film thickness (T4 shown in FIG. 4(b)) in the sub-portion 21. By being configured in this way, the lead terminals 36 can be more reliably protected from dust, moisture, physical impact, etc. However, in the present invention, the minimum film thickness T5 in the main portion 23 may be thinner than the maximum film thickness T4 in the sub-portion 21. Even with such a configuration, according to this embodiment, in the second coating step, the coating resin 20 is laminated on the coating resin 20 cured in the first curing step to apply the coating resin 20, so that the thickness of the minimum film thickness T5 in the main portion 23 can be sufficiently ensured. Therefore, the lead terminals 36 can be well protected from dust, moisture, physical impact, etc. In a plan view, as shown in FIG. 4(a), it is preferable that the entire outer contour line of each lead terminal 36 is arranged in a region inside the outer contour line of the main portion 23 of the coating resin 20, and more preferably, the entire outer contour line of each fillet 52 is arranged in a region inside the outer contour line of the main portion 23 of the coating resin 20. Further, in the coating resin 20, a step (depression) (not shown) may be formed in the intermediate portion 27 applied between the lead terminals 36.

[0041] The minimum film thickness of the sub-portion 21 of the coating resin 20 is not particularly limited, but for example, it is preferably 10 μm or more. The minimum film thickness T5 of the main portion 23 of the coating resin 20 is not particularly limited, but for example, it is preferably 40 μm or more.

[0042] Hereinafter, with reference to FIGS. 5(a) to 6(c), the manufacturing method of the printed circuit board 100 with electronic components according to this embodiment will be described in more detail.

[0043] Also in the case of this embodiment, similar to the first embodiment, a mounting step of mounting the electronic component 30 on the base material 10 and a coating step of coating at least a part of the electronic component 30 with the coating resin 20 are performed in this order. The coating step includes a first coating step of applying the coating resin 20 to at least a part of the electronic component 30, a first curing step of curing the coating resin 20 applied in the first coating step, a second coating step of applying the coating resin 20 by laminating it on the coating resin 20 cured in the first curing step, and a second curing step of curing the coating resin 20 applied in the second coating step.

[0044] More specifically, in the case of this embodiment, first, in the mounting step, a base material 10 in which a plurality of through holes 15 are formed is prepared. Then, as shown in FIGS. 5(a) and 6(a), the corresponding lead terminals 36 are joined to the land portions 44 of the respective through holes 15 via solder 50. In this way, the electronic component 30 is mounted on the base material 10. Next, as shown in FIGS. 5(b) and 6(b), in the first coating step, the coating resin 20 is applied over each lead terminal 36 and fillet 52, and in a plan view, over one surface 10a of the base material 10 and a portion located around the electronic component 30 in the conductor pattern 40. Then, as the first curing step, the coating resin 20 applied in the first coating step is cured. Subsequently, as shown in FIGS. 5(c) and 6(c), as the second coating step, the coating resin 20 is applied by laminating it on the coating resin 20 cured in the first curing step. Then, as the second curing step, the coating resin 20 applied in the second coating step is cured.

[0045] Here, also in the case of this embodiment, similar to the first embodiment, the range where the coating resin 20 is applied in the second coating step is preferably a region inside the outer contour line of the coating resin 20 cured in the first curing step in a plan view. That is, in the second coating step, it is preferable to apply the coating resin 20 in a range narrower than the formation range of the coating resin 20 cured in the first curing step. In the coating process, it is preferable to coat the entire fillet 52 (excluding the portion in contact with one surface 10a). More specifically, for example, in the first coating step and the second coating step, the coating resin 20 is applied so as to cover the entire fillet 52. In a plan view, the entire outer contour line of the fillet 52 is located in a region inside the outer contour line of the main portion 23 of the coating resin 20. When the upper end portion of the lead terminal 36 is exposed from the fillet 52 as in the examples shown in FIGS. 5(a) and 6(a), in the coating process, it is preferable to coat the entire portion of the upper end portion of the lead terminal 36 that is exposed from the fillet 52 with the coating resin 20.

[0046] <Modification of the Second Embodiment> Next, the second embodiment will be described with reference to FIGS. 7(a) and 7(b). Modification example will be described. The printed circuit board 100 with electronic components according to this embodiment is different from the printed circuit board 100 with electronic components according to the above-described second embodiment in the points described below, and is configured in the same manner as the printed circuit board 100 with electronic components according to the above-described second embodiment in other points.

[0047] In the case of this modification, as shown in FIGS. 7(a) and 7(b), the main body portion 35 is different from the second embodiment in that it is mounted on one surface 10a side of the base material 10. More specifically, for example, the main body portion 35 is arranged in a lying-down posture on one surface 10a of the base material 10, and the other surface 30b provided with each lead terminal 36 faces the horizontal direction (a direction orthogonal to the vertical direction). Further, each lead terminal 36 is arranged side by side in the horizontal direction, for example, and extends horizontally along one surface 10a of the base material 10. And the coating resin 20 is formed on, for example, one surface 1 0a side of the base material 10 and covers above each lead terminal 36. Even with such a configuration, the coating resin 20 can satisfactorily protect each lead terminal 36 from dust, moisture, physical impact, etc.

[0048] Also in the case of this modified example, in a plan view, the entire outer shape line of each lead terminal 36 is arranged in a region inside the outer shape line of the coating resin 20. In the example shown in FIG. 7(a), the main part 23 of the coating resin 20 is formed so as to cover each lead terminal 36 in series. On the other hand, the main body part 35 is exposed from the coating resin 20, for example, in a plan view. Further, a part of the coating resin 20 is in contact with, for example, the other surface 30b of the main body part 35. Note that the coating resin 20 may cover, for example, above the main body part 35.

[0049] As described above, each embodiment has been described with reference to the drawings, but these are examples of the present invention, and various configurations other than the above can also be adopted.

[0050] The above embodiments include the following technical ideas. (1) A method for manufacturing a printed circuit board with electronic components, comprising an insulating base material, electronic components mounted on the base material, and an insulating coating resin covering at least a part of the electronic components, a mounting step of mounting the electronic components on the base material, a coating step of coating at least a part of the electronic components with the coating resin, which are performed in this order, wherein the coating step includes a first coating step of applying the coating resin to at least a part of the electronic components, a first curing step of curing the coating resin applied in the first coating step, a second coating step of applying the coating resin by laminating it on the coating resin cured in the first curing step, a second curing step of curing the coating resin applied in the second coating step, and is a method for manufacturing a printed circuit board with electronic components. (2) The range for applying the coating resin in the second coating step is an area inside the outer contour line of the coating resin cured in the first curing step in a plan view, in the manufacturing method of the printed circuit board with electronic components according to (1). (3) The electronic component is a rectangular surface mount component. In the coating step, the entire rectangular surface mount component is coated with the coating resin, in the manufacturing method of the printed circuit board with electronic components according to (1) or (2). (4) The electronic component has lead terminals. In the coating step, at least the lead terminals are coated with the coating resin, in the manufacturing method of the printed circuit board with electronic components according to (1) or (2). (5) An insulating base material, electronic components mounted on the base material, an insulating coating resin covering the electronic components, A printed circuit board with electronic components comprising: The coating resin has a main part covering at least a part of the electronic component and a sub - part disposed around the main part. A printed circuit board with electronic components, wherein the thickness of the main part is thicker than the thickness of the sub - part, and there is a step at the boundary between the main part and the sub - part. (6) The printed circuit board with electronic components according to (5), wherein the height of the step is greater than the thickness of the sub - part.

Explanation of Signs

[0051] 10 Base material 10a One side 10b The other side 15 Through - hole 20 Coating resin 21 Sub - part 23 Main part 25 Step 30 Electronic component 30a One side 30b The other side 35 Body part 36 Lead terminal 40 Conductor pattern 44 Land portion 50 Solder 52 Fillet 100 Printed circuit board with electronic components

Claims

1. A method for manufacturing a printed circuit board with electronic components, comprising an insulating base material, electronic components mounted on the base material, and an insulating coating resin covering at least a part of the electronic components, the method comprising: a mounting step of mounting the electronic components on the base material; a coating step of coating at least a part of the electronic components with the coating resin; performing these steps in this order, wherein the coating step includes: a first coating step of applying the coating resin to at least a part of the electronic components; a first curing step of curing the coating resin applied in the first coating step; a second coating step of laminating and applying the coating resin on the coating resin cured in the first curing step; a second curing step of curing the coating resin applied in the second coating step; and in the second coating step, the range where the coating resin is applied is a region inside the outer contour line of the coating resin cured in the first curing step in a plan view, and the coating resin is applied such that a step is formed at the boundary between the coating resin cured in the first coating step and the coating resin to be applied in the second coating step. A method for manufacturing a printed circuit board with electronic components.

2. The method for manufacturing a printed circuit board with electronic components according to claim 1, wherein in the second coating step, the coating resin is applied such that the height of the step is greater than the maximum film thickness of the coating resin cured in the first coating step.

3. The electronic component is a rectangular surface mount component, and in the coating step, the entire rectangular surface mount component is covered with the coating resin. The method for manufacturing a printed circuit board with electronic components according to claim 1 or 2.

4. The electronic component has lead terminals, and in the coating step, at least the lead terminals are covered with the coating resin. The method for manufacturing a printed circuit board with electronic components according to claim 1 or 2.

5. A printed circuit board with electronic components, comprising an insulating base material, electronic components mounted on the base material, and an insulating coating resin covering the electronic components, wherein the coating resin has a main part covering at least a part of the electronic components and a sub-part arranged around the main part. ​ A printed circuit board with an electronic component, in which the film thickness of the main part is thicker than that of the sub part, and a step exists at the boundary between the main part and the sub part.

6. The printed circuit board with an electronic component according to claim 5, wherein the height of the step is larger than the thickness of the sub part.

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