JP2017212410A - Printed-wiring board and manufacturing method thereof - Google Patents

Abstract

When the electrode width of an electronic component is narrow, the connection area between the electrode and the via is reduced, and the connection reliability is reduced.
A printed wiring board includes a substrate having a component accommodating portion, a component having an electrode accommodated in the component accommodating portion, and an insulating resin layer laminated on the upper and lower surfaces of the substrate. And vias 15a formed in the insulating resin layer 14 and directly connected to the electrodes 13a of the component 13. The via 15a has a shape that narrows from the end near the component 13 toward the other end.
[Selection] Figure 1

Description

  The present disclosure relates to a printed wiring board incorporating an electronic component and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, a printed wiring board is known in which an electronic component is accommodated in a component accommodating portion, and a gap between the electronic component and the inner wall of the component accommodating portion is filled with a synthetic resin. Such a printed wiring board is described in Patent Document 1, for example. In a printed wiring board in which an electronic component is accommodated in a component accommodating portion, for example, a via having a small diameter on the electrode side is connected to an electrode of the electronic component, and is electrically connected to a conductor of another layer. However, when the electrode width of the electronic component is narrow, there is a concern that the connection area between the electrode and the via becomes small, and the connection reliability is lowered.

JP-A-11-330304

  A printed wiring board according to the present disclosure includes a substrate having a component accommodating portion, a component having an electrode accommodated in the component accommodating portion, an insulating resin layer laminated on the upper and lower surfaces of the substrate, and an insulating resin layer formed on the component. And a via that is directly connected to the electrode, and the via has a shape that narrows from an end near the component toward the other end.

  In the printed wiring board manufacturing method according to the present disclosure, a component having an electrode is accommodated in a substrate having a component accommodating portion, an insulating resin layer is stacked on the upper and lower surfaces of the substrate, and the insulating resin layer is directly connected to the electrode of the component. For forming the via hole, the laser direct structuring is formed so as to have a shape that narrows from the end close to the part toward the other end, and the via is formed in the via forming hole. Form.

FIG. 1A is a cross-sectional view illustrating an embodiment of a printed wiring board according to the present disclosure, and FIG. 1B is an enlarged perspective view of a region X illustrated in FIG. 2A to 2D are process explanatory views showing an embodiment of a method for manufacturing a printed wiring board according to the present disclosure. 3A is a cross-sectional view illustrating another embodiment of the printed wiring board according to the present disclosure, and FIG. 3B is an enlarged view of a region Y illustrated in FIG.

  One embodiment of a printed wiring board according to the present disclosure will be described with reference to FIGS. A printed wiring board 10 shown in FIG. 1A includes a substrate 11 having a component accommodating portion 12, a component 13 having an electrode 13 a accommodated in the component accommodating portion 12, and an insulating resin laminated on the upper and lower surfaces of the substrate 11. A layer 14 and a via 15 a for connecting to the electrode 13 a of the component 13 formed in the insulating resin layer 14 are provided.

  The substrate 11 includes a core layer 11a and an insulating layer 11b. The core layer 11a is not particularly limited as long as it is made of an insulating material. Examples of the insulating material include organic resins such as epoxy resins, bismaleimide-triazine resins, polyimide resins, and polyphenylene ether resins. These organic resins may be used in combination of two or more.

  When an organic resin is used as a material having insulating properties, it is preferable to use the organic resin mixed with a reinforcing material. Examples of the reinforcing material include insulating fabric materials such as glass fiber, glass nonwoven fabric, aramid nonwoven fabric, aramid fiber, and polyester fiber. Two or more reinforcing materials may be used in combination. Further, the insulating material may include inorganic fillers such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide.

  The insulating layer 11b is formed on the upper and lower surfaces of the core layer 11a. The insulating layer 11b is not particularly limited as long as it is made of an insulating material, and examples thereof include the above-described insulating material. The insulating layer 11b may be the same material as the core layer 11a or may be a different material.

  A first wiring pattern 111 is formed on the surfaces of the core layer 11a and the insulating layer 11b. The first wiring pattern 111 is not limited as long as it is made of a conductive material. Examples of the conductive material include metals and conductive resins. Among these conductive materials, copper is preferable in terms of workability such as etching. For example, the first wiring pattern 111 is formed by copper plating such as chemical copper plating (electroless copper plating) or electrolytic copper plating, copper foil, or copper foil. Further, the first wiring pattern 111 may be formed by forming holes in the core layer 11a and the insulating layer 11b by laser processing, and performing plating on the holes.

  Further, a through hole 111a is formed in the core layer 11a in order to electrically connect the upper and lower surfaces of the substrate 11. The through hole 111a penetrates the upper and lower surfaces of the core layer 11a. The through hole 111a is formed of a conductor layer 111a 'made of metal plating such as copper plating. The conductor layer 111a 'is connected to the first wiring pattern 111 formed on the surface of the core layer 11a.

  A component housing portion 12 is formed on the substrate 11. The component accommodating portion 12 is a through hole formed in the substrate 11 and is obtained by removing a part of the substrate 11 by laser processing, mold processing, or the like. A component 13 having an electrode 13 a is accommodated in the component accommodating portion 12.

  The component 13 is not particularly limited as long as it is a component that is generally surface-mounted and incorporated in a printed wiring board, and examples thereof include electronic components such as semiconductor elements, capacitors, and resistors. In particular, the use of a fine component having a narrow electrode width, for which it is difficult to ensure connection reliability, as the component 13 is more effective in ensuring connection reliability. For example, 0402 (0.4 mm × A 0.2 mm) size component, a 0603 (0.6 mm × 0.3 mm) size component, or the like may be used.

  In addition to the component 13, the component housing portion 12 is filled with a sealing resin 12 a. By filling the component housing portion 12 with the sealing resin 12a, the component 13 is fixed at a desired position. The sealing resin 12a is not particularly limited, and examples thereof include a photo-curing resin, an ultraviolet curable resin, and a thermosetting resin, and specific examples include an epoxy resin, an acrylic resin, a polyimide resin, and a polyphenylene ether resin. The sealing resin 12a may further contain an inorganic filler such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide.

  Insulating resin layers 14 are formed on the upper and lower surfaces of the substrate 11. The insulating resin layer 14 is laminated in two layers and covers the component housing portion 12 in which the component 13 is housed. The insulating resin layer 14 is not particularly limited as long as it is formed of an insulating material. Examples of the insulating material include organic resins such as epoxy resin, bismaleimide-triazine resin, and polyimide resin. These organic resins may be used in combination of two or more.

  A second wiring pattern 141 is formed on the surface of the insulating resin layer 14. The second wiring pattern 141 is not limited as long as it is made of a conductive material. Since the second wiring pattern 141 is formed in the same procedure as the first wiring pattern 111, detailed description is omitted.

  Vias 15 for electrically connecting the layers are formed in the substrate 11 (core layer 11a and insulating layer 11b) and insulating resin layer. The via 15 includes a first via 15a directly connected to the electrode 13a of the component 13 and a second via 15b other than the first via 15a.

  FIG. 1B shows an enlarged perspective view of the region X in FIG. FIG. 1B is a diagram for explaining the shape of the first via 15a in more detail, and the insulating resin layer 14 formed between the electrode 13a and the second wiring pattern 141 is omitted. . The first via 15a is directly connected to the electrode 13a of the component 13, and has a shape that becomes narrower from the end on the electrode 13a side toward the other end as shown in FIG. . In other words, the first via 15 a has a shape that becomes narrower from the end near the component 13 toward the other end. The difference between the diameter D1 of the end on the electrode 13a side and the diameter D2 of the other end is not particularly limited. For example, in order to further improve the connection reliability, it is preferably 10 μm or more.

  The second via 15b is a via other than the first via 15a. That is, the via is not directly connected to the electrode 13a of the component 13. Unlike the first via 15 a, the second via 15 b has a shape that becomes thicker from the end near the component 13 toward the other end. The second via 15b is formed to electrically connect the layers, and is connected to the first wiring pattern 111 and the second wiring pattern 141 described above.

  The via 15 (first via 15a and second via 15b) is formed of a conductor. Examples of such a conductor include copper, aluminum, gold, and silver. Furthermore, a conductive paste in which a powder containing these metals as a main component is mixed with a synthetic resin may be used.

  As described above, the printed wiring board of the present disclosure has a shape in which the first via that is directly connected to the electrode of the component is narrowed from the end on the electrode side toward the other end. Therefore, even if the electrode width of a component is narrow, or a laser via position shift or a built-in component mounting shift occurs, a sufficient connection area between the via and the electrode can be secured. Therefore, the printed wiring board of the present disclosure can exhibit excellent connection reliability.

  Next, the manufacturing method of the printed wiring board which concerns on one Embodiment of this invention is demonstrated based on FIG. The same members as those of the printed wiring board 10 of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2A, a substrate 11 on which a component housing portion 12 is formed is prepared. As described above, the component housing portion 12 is formed by removing a part of the substrate 11 by, for example, laser processing, mold processing, or the like. The substrate 11 includes the core layer 11a and the insulating layer 11b as described above.

  A through hole 111a is formed in the core layer 11a. The through hole 111a is formed as follows, for example. First, a through-hole pilot hole is formed by drilling or the above-described laser processing so as to penetrate the upper and lower surfaces of the core layer 11a. Thereafter, a through hole 111a is obtained by depositing a conductor layer 111a 'made of metal plating such as copper plating on the inner wall surface of the through hole pilot hole.

  A first wiring pattern 111 is formed on the surface of the core layer 11a. The first wiring pattern 111 is formed as follows, for example. First, a dry film (not shown) as an etching resist is attached to an insulating plate having a conductor (copper foil) formed on the surface by a known method, and is exposed and developed. After that, etching is performed and the dry film is peeled off, whereby the core layer 11a having the first wiring pattern 111 formed on the surface is obtained. The first wiring pattern 111 and the through hole 111a are connected.

In the insulating layer 11b, a second via 15b connected to the first wiring pattern 111 is formed. The second via 15b is as described above, and detailed description thereof is omitted. The second via 15b is formed as follows. First, a hole for forming the second via 15b is formed in the insulating layer 11b by a CO ₂ laser, a UV-YAG laser, or the like. The second via 15b is obtained by filling the hole for forming the second via 15b with a conductor. The conductor is as described above, and detailed description thereof is omitted. The conductor is filled by plating or the like.

  Next, insulating layers 11b are formed on the upper and lower surfaces of the core layer 11a. The insulating layer 11b is formed, for example, by placing prepregs on the upper and lower surfaces of the core layer 11a and hot pressing. A first wiring pattern 111 is also formed on the surface of the insulating layer 11b. The method for forming the first wiring pattern 111 is not particularly limited. For example, a conductor (copper foil) is placed on the surface of the prepreg and subjected to hot pressing, and then, similarly to the above-described method, a dry film is stuck by a known method, exposed and developed, and then etched.

  As shown in FIG. 2B, a release film 16 is attached to the lower surface of the substrate 11. The release film 16 is a member for temporarily fixing the component so that the component does not fall when the component is accommodated in the component accommodating portion 12, and the contact surface with the component has adhesiveness. The release film 16 is obtained, for example, by applying an adhesive to a polyethylene terephthalate (PET) film. Instead of PET film, for example, MagiCarrier (manufactured by Kyosei Co., Ltd.), flex carrier (manufactured by UMI Co., Ltd.) that can be used repeatedly may be used.

  Next, as illustrated in FIG. 2C, the component 13 is accommodated in the component accommodating portion 12. The component 13 is accommodated so that the electrode 13a is in contact with the release film 16 with the electrode 13a facing downward. After accommodating the component 13 in the component accommodating part 12, in order to fix the component 13, it is filled with sealing resin 12a. The sealing resin 12a is as described above, and a description thereof is omitted.

  As shown in FIG. 2D, the release film 16 is removed, and the insulating resin layers 14 are formed on the upper and lower surfaces of the substrate 11. Two insulating resin layers 14 are laminated on the upper and lower surfaces of the substrate 11, respectively. The insulating resin layer 14 is formed, for example, by placing a prepreg on the upper and lower surfaces of the substrate 11 and hot pressing. A second wiring pattern 141 is formed on the surface of each insulating resin layer 14. The method for forming the second wiring pattern 141 is not particularly limited, and the second wiring pattern 141 is formed by the same method as that for the first wiring pattern 111. For example, a conductor (copper foil) is placed on the surface of the prepreg and subjected to hot pressing, and then, similarly to the above-described method, a dry film is stuck by a known method, exposed and developed, and then etched.

  Next, the first via 15 a is formed in the insulating resin layer 14 in order to electrically connect the electrode 13 a of the component 13 and the second wiring pattern 141. As described above, the first via 15a has a shape that narrows from the end on the electrode 13a (component 13) side toward the other end. In order to form a via having such a shape, a hole for forming the first via 15a is formed in the insulating resin layer 14 in contact with the electrode 13a of the component 13 by laser direct structuring (LDS). The LDS apparatus is commercially available from, for example, LPKF Laser & Electronics Co., Ltd. The first via 15a is obtained by filling the hole for forming the first via 15a with a conductor. The conductor is as described above, and the description is omitted. The conductor is filled by plating or the like.

  Further, a second via 15 b for connecting the second wiring patterns 141 or between the first wiring pattern 111 and the second wiring pattern 141 is formed. The method for forming the second via 15b is as described above, and detailed description thereof is omitted. In this way, the printed wiring board 10 shown in FIG. 1A is obtained.

  The printed wiring board of this indication is not limited to the above-mentioned embodiment. For example, in the printed wiring board 10 described above, the first via 15 a is connected to the electrode 13 a formed on the bottom surface of the component 13. However, as in the printed wiring board 20 shown in FIG. 3A, the first via 15 a ′ is formed not only on the electrode 13 a formed on the bottom surface of the component 13 but also on the electrode 13 a formed on the end surface of the component 13. May be. That is, when the electrode 13a is formed on the end face of the component 13 and in the vicinity of the end face, a part of the first via 15a 'may be formed on the electrode 13a formed on the end face.

  If vias are formed on the electrodes 13a formed on the end face and bottom surface of the component 13 as in the first via 15a ', the electrode width of the component is narrowed, the laser via position shift or the built-in component mounting shift occurs. In addition, a sufficient connection area between the first via 15a ′ and the electrode 13a can be secured. Therefore, more excellent connection reliability is exhibited.

  In the printed wiring board 10 shown in FIG. 1A described above, the substrate 11 includes a core layer 11a and an insulating layer 11b. However, the substrate may be formed of only the core layer, and two or more insulating layers may be stacked.

  In the printed wiring board 10 shown in FIG. 1A described above, two insulating resin layers 14 are laminated. However, the insulating resin layer may be only one layer, or three or more layers may be laminated.

  Further, in the printed wiring board 10 shown in FIG. 1A described above, unlike the first via 15a, the second via 15b has a shape that becomes thicker from the end closer to the component 13 toward the other end. Have. However, like the first via, the second via may have a shape that narrows from the end close to the component toward the other end.

DESCRIPTION OF SYMBOLS 10, 20 Printed wiring board 11 Board | substrate 11a Core layer 111a Through hole 111a 'Conductor layer 11b Insulating layer 111 1st wiring pattern 12 Component accommodating part 12a Sealing resin 13 Components 13a Electrode 14 Insulating resin layer 141 2nd wiring pattern 15 Via

Claims (4)

A substrate having a component housing portion;
A component having an electrode housed in a component housing portion;
An insulating resin layer laminated on the upper and lower surfaces of the substrate;
A via formed in an insulating resin layer and directly connected to the electrode of the component;
With
The printed wiring board, wherein the via has a shape that narrows from an end near the component toward the other end.   The printed wiring board according to claim 1, wherein the via has a difference of 10 μm or more in a diameter between both ends.   The electrode of the component is formed on at least one end face of the component and in the vicinity of the end surface, and a part of the via is connected to an electrode formed on the end surface of the component. Printed wiring board.   A component having an electrode is accommodated in a substrate having a component accommodating portion, an insulating resin layer is laminated on the upper and lower surfaces of the substrate, and a hole for forming a via for directly connecting to the electrode of the component is formed in the insulating resin layer. A method of manufacturing a printed wiring board, which is formed by structuring so as to have a shape that narrows from an end close to a component toward the other end, and a via is formed in a hole for forming a via.

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