JP6316616B2 - Built-in component board - Google Patents

Description

  The present invention relates to a component-embedded substrate in which electronic components such as chip resistors are embedded in an insulating resin layer, and in particular, other electronic components mounted on the resin layer are electrically connected to the built-in electronic component. The present invention relates to a component-embedded substrate.

  In recent years, electronic components such as chip resistors are mounted not only on the circuit board surface but also on the inner layer to increase the component mounting density as electronic devices become smaller and lighter and circuit configurations become more complex. A mold substrate is in practical use.

  In this type of component-embedded substrate, an electronic component is usually embedded in a wiring substrate made of an insulating resin layer, and then a via hole is formed by irradiating the resin layer with a laser beam, and copper plating is formed in the via hole. By forming a connection via made of processing or the like, the external electrode of the built-in electronic component and the connection via are connected (for example, see Patent Document 1). Here, since an opaque resin is generally used as the resin layer, the external electrodes of the built-in electronic components cannot be visually observed when forming the via hole in the resin layer, and the via hole formation position is shifted. There is a risk that the external electrode of the electronic component is not correctly connected.

  Therefore, a chip resistor (electronic component) is prepared in advance so that the area of the back electrode is set larger than that of the front electrode so that there is no problem even if the via hole formation position and the external electrode of the electronic component are slightly shifted. In addition, a component-embedded substrate has been proposed in which such a chip resistor is embedded in a resin layer with the surface electrode formation surface facing downward (see, for example, Patent Document 2).

  In the prior art disclosed in Patent Document 2, since the back electrode of the electronic component built in the resin layer is formed in a large area, when forming the via hole by irradiating the resin layer with laser light, Even if the formation position is slightly deviated from the normal position, the via hole and the external electrode (back electrode) can be reliably connected.

JP 2001-53447 A JP 2011-199188 A

  However, miniaturization of electronic components used for component-embedded substrates tends to be promoted. For example, in the case of a small chip resistor called 0603 size (0.6 mm × 0.3 mm), a back electrode serving as an external electrode Therefore, even if the conventional technique disclosed in Patent Document 2 is adopted, a sufficient effect cannot be expected. In particular, when an insulating resin (for example, epoxy resin) having a large shrinkage rate at the time of curing is used as the resin layer, the mounting position of the electronic component is displaced with the shrinkage of the insulating resin. When a small electronic component having a limit in size is used, there is a possibility that the connection with the external electrode becomes incomplete due to a slight misalignment of the via hole.

  Further, when another electronic component is mounted on the wiring pattern formed on the surface of the resin layer, and this electronic component is electrically connected to the electronic component embedded in the resin layer, the conventional technology disclosed in Patent Literature 1 and Patent Literature 2 is used. As described above, when the via hole is formed in the insulating layer and the wiring pattern and the external electrode of the built-in component are electrically connected, the via hole prevents the wiring board from being thinned. In particular, in the case of a multilayer substrate in which these two electronic components are each incorporated in an insulating layer, the length of the via holes formed in each layer is accumulated, resulting in a very thick wiring board as a whole. Since the distance from the surface of the insulating layer to the external electrode of the electronic component embedded in the lower layer becomes longer, there arises a problem that drilling of the via hole and plating formation in the via hole become difficult.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to allow other electronic components to be easily and reliably conducted with respect to a built-in electronic component and to be suitable for thinning. The object is to provide a component-embedded substrate.

To achieve the above object, the component-embedded substrate of the present invention has the first electronic component having the external electrode embedded in the base substrate and the second electronic component having the external electrode mounted on the base substrate. in component-embedded type substrate being, said being set to a larger area than the external electrode of the first said external electrode of the electronic component and the second electronic component, Ru into conduction overlapping these two external electrodes each other directly Thus, a part of the external electrode of the first electronic component is exposed from the end surface of the second electronic component.

In the component built-in type substrate configured as described above, the external electrode of the first electronic component built in the base substrate and the external electrode of the second electronic component surface-mounted on the base substrate are directly overlapped without via holes. Thus, since the conductive state is established, it is possible to eliminate the conduction failure due to the positional deviation of the via hole, and it is possible to reduce the thickness by omitting the via hole. In addition, the external electrode of the first electronic component is set to have a larger area than the external electrode of the second electronic component, and by overlapping these external electrodes, a part of the external electrode of the first electronic component is the second. Since it is exposed from the external electrode of the electronic component, when the first electronic component and the second electronic component are fixed using an adhesive material such as a conductive adhesive or solder (cream solder), the adhesive material is It becomes easy to protrude from the adhesion surface of both external electrodes to the exposed part of the external electrode, and the fixing property can be improved.

  In the above configuration, the means for incorporating the first electronic component in the base substrate is not particularly limited, but the base substrate is provided with an embedding hole, and the first electron is placed inside the resin layer filled in the embedding hole. It is preferable to embed the part.

In the above configuration, the second electronic component has an external electrode fixed with the external electrode of the first electronic component as the connection land, and an external electrode fixed with the wiring pattern on the base substrate as the connection land. Of the pair of external electrodes provided in the second electronic component, for one of the external electrodes, the external electrode of the first electronic component can be used as the connection land, so that the connection land of the wiring pattern required on the base substrate can be used. Can be reduced.

According to the component-embedded substrate of the present invention, the second electronic component surface-mounted on the base substrate can be easily and reliably conducted with respect to the first electronic component embedded in the base substrate, and a via hole is omitted. It is possible to reduce the thickness as much as possible.

It is sectional drawing of the component built-in type board | substrate which concerns on the example of 1st Embodiment of this invention. It is explanatory drawing which shows the manufacturing process of the component built-in type board | substrate which concerns on the example of 1st Embodiment. It is sectional drawing of the component built-in type board | substrate which concerns on the 2nd Example of this invention. It is sectional drawing of the component built-in type board | substrate which concerns on the example of 3rd Embodiment of this invention. It is sectional drawing of the component built-in type board | substrate which concerns on the example of 4th Embodiment of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the invention will be described. As shown in FIG. 1, a component-embedded substrate 1 according to a first embodiment of the present invention is a base made of an insulating resin such as epoxy resin or polyimide. Mainly by the substrate 2, the first electronic component 3 built in the base substrate 2, the second electronic component 4 mounted on the base substrate 2, the wiring pattern 5 provided on the surface of the base substrate 2, etc. It is configured.

  An embedding hole 2a is formed in the base substrate 2, and the first electronic component 3 is embedded inside an insulating resin layer 6 filled in the embedding hole 2a. The first electronic component 3 is, for example, a chip resistor. Although details are not shown, the upper surface of the first electronic component 3 is connected to a pair of first surface electrodes or a first surface electrode. A resistor, a protective layer that covers the resistor, a second surface electrode that covers an end of the protective layer, an external electrode 3a that covers the second surface electrode, and the like, are provided on the lower surface side of the first electronic component 3. A back electrode is provided.

  The second electronic component 4 is also a chip resistor, and details thereof are omitted. However, a pair of surface electrodes, a resistor connected to the surface electrode, and a resistor are provided on the upper surface side of the second electronic component 4. A covering protective layer is provided, and a pair of backside electrodes functioning as the external electrodes 4 a are provided on the lower surface side of the second electronic component 4. The second electronic component 4 is mounted on the base substrate 2 so that one external electrode 4a directly overlaps the external electrode 3a of the first electronic component 3, and these external electrodes 3a and 4a are connected using a conductive adhesive. At the same time, the other external electrode 4a of the second electronic component 4 is connected to the wiring pattern 5 using a conductive adhesive.

  Next, a manufacturing method of the component built-in substrate 1 configured as described above will be described with reference to FIG.

  First, as shown in FIG. 2A, after a wiring material 7 made of copper foil is attached to one surface of the base substrate 2, the wiring material 7 is patterned by using a known photolithography technique. As shown in FIG. 2B, the wiring pattern 5 is formed on one side of the base substrate 2. Next, by irradiating the base substrate 2 with, for example, a laser beam, an embedding hole 2a is formed at a predetermined position of the base substrate 2 as shown in FIG.

  Next, the base substrate 2 is inverted in this state, and as shown in FIG. 2D, a release plate 8 is attached to the wiring pattern 5 to close one opening end of the embedding hole 2a. As shown in FIG. 2 (e), the first electronic component 3 is inserted into the embedding hole 2 a and placed on the release plate 8. At this time, since the first electronic component 3 is housed in the embedding hole 2a in a horizontal posture with the external electrode 3a facing downward, the surfaces of the pair of external electrodes 3a abut against the flat peeling plate 8. .

  Next, as shown in FIG. 2 (f), the upper surface of the base substrate 2 is covered with a thermoplastic resin film such as PEEK or PEI, and this is heated and pressurized to form a resin layer 6 inside the embedding hole 2a. Fill. Thereafter, when the base substrate 2 is reversed and the release plate 8 is peeled off, the external electrodes 3a and the wiring patterns 5 of the first electronic component 3 are exposed from the upper surface of the base substrate 2, as shown in FIG. These external electrodes 3a and the wiring pattern 5 are located in the same plane.

  Next, after applying a conductive adhesive to predetermined portions of the external electrode 3a and the wiring pattern 5 of the first electronic component 3, the second electronic component 4 is placed on the base substrate 2 as shown in FIG. 2 (h). By mounting, both external electrodes 4a of the second electronic component 4 are bonded to the external electrodes 3a of the first electronic component 3 and the wiring pattern 5 through a conductive adhesive. As a result, the external electrode 3a of the first electronic component 3 incorporated in the embedding hole 2a of the base substrate 2 and the external electrode 4a of the second electronic component 4 mounted on the surface of the base substrate 2 are connected via via holes. Instead, they are superposed directly into a conductive state, and the component-embedded substrate 1 having a mounting structure as shown in FIG. 1 is completed.

  As described above, in the component-embedded substrate 1 according to the first embodiment, the resin layer 6 is filled in the embedding hole 2 a of the base substrate 2, and the first component that is the embedded component embedded in the resin layer 6. Since the external electrode 3a of the electronic component 3 and the external electrode 4a of the second electronic component 4 which is a surface mounting component mounted on the base substrate 2 are directly superimposed without via holes, they are in a conductive state. It is possible to eliminate the conduction failure due to the position shift of the via hole and to reduce the thickness by omitting the via hole.

  Further, the external electrode 3a of the first electronic component 3 embedded in the resin layer 6 and the wiring pattern 5 provided on the surface of the base substrate 2 are located in the same plane, and the external electrode 3a and the wiring pattern 5 are arranged. Since the external electrodes 4a of the second electronic component 4 are overlapped with each other, the external electrodes 4a of the second electronic component 4 are in close contact with the external electrodes 3a of the first electronic component 3 in a parallel posture without being inclined. As a result, the reliability of conduction between the two can be made extremely stable.

  Here, in the above-described first embodiment, both the external electrodes 4a of the second electronic component 4 are made of conductive adhesive with respect to the external electrodes 3a of the first electronic component 3 and the wiring pattern 5 on the base substrate 2, respectively. However, it is also possible to use solder instead of the conductive adhesive as in the second and third embodiments described below.

  As shown in FIG. 3, in the component-embedded substrate 20 according to the second embodiment of the present invention, the external electrode 3a of the first electronic component 3 and the external electrode 4a of the second electronic component 4 are substantially the same in plan view. However, since the external electrode 4a of the second electronic component 4 is superimposed on the external electrode 3a of the first electronic component 3 so as to be shifted in the in-plane direction of the mutual contact surface, the first electron is accordingly accompanied. A part of the external electrode 3 a of the component 3 is exposed from the end surface of the second electronic component 4.

  In the component-embedded substrate 20 according to the second embodiment configured as described above, the first electronic component 3 and the second electronic component 4 are bonded using an adhesive material such as a conductive adhesive or solder (cream solder). When the adhesive material is fixed, the adhesive material easily protrudes from the adhesion surface of the external electrodes 3a and 4a to the exposed portion of the external electrode 3a, so that a place for the adhesive material to escape is secured and the adhesiveness can be improved. In particular, when solder is used as the adhesive material, the solder that protrudes from the adhesive surface to the exposed portion of the external electrode 3a forms a fillet 9 on the end surface of the second electronic component 4, so the first electronic component 3 and the second electronic component The adhesion of No. 4 is very good.

  As shown in FIG. 4, in the component-embedded substrate 30 according to the third embodiment of the present invention, the external electrode 3a of the first electronic component 3 is set to have a larger area than the external electrode 4a of the second electronic component 4. A portion of the external electrode 3a of the first electronic component 3 is exposed from the end face of the second electronic component 4 by overlapping the smaller external electrode 4a on the larger external electrode 3a. . At that time, the area itself of the external electrode 3a provided on the upper surface side of the first electronic component 3 may be increased, and the external electrode 4a of the second electronic component 4 may be electrically connected to the external electrode 3a. The first electronic component 3 is provided with an end face electrode that conducts the surface electrode and the back face electrode, and an external electrode portion that covers the end face electrode, the front face electrode, and the back face electrode is provided. On the other hand, if the external electrode 4a of the second electronic component 4 is made conductive, the first electronic component 3 can be easily provided with a large and flat external electrode.

  Also in the component-embedded substrate 30 according to the third embodiment configured as described above, the first electronic component 3 and the second electronic component 4 are bonded using an adhesive material such as a conductive adhesive or solder (cream solder). When the adhesive material is fixed, the adhesive material easily protrudes from the adhesion surface of the external electrodes 3a and 4a to the exposed portion of the external electrode 3a, so that a place for the adhesive material to escape is secured and the adhesiveness can be improved. In particular, when solder is used as the adhesive material, the solder that protrudes from the adhesive surface to the exposed portion of the external electrode 3a forms a fillet 9 on the end surface of the second electronic component 4, so the first electronic component 3 and the second electronic component The adhesion of No. 4 is very good.

  FIG. 5 is a cross-sectional view of a component-embedded substrate 40 according to a fourth embodiment of the present invention. The component-embedded substrate 40 includes the first electronic component 3 and the second electronic component 4 described above as insulating layers. It is a built-in multilayer substrate. That is, the first electronic component 3 embedded in the resin layer 6 of the base substrate 2 and the second electronic component 4 mounted on the base substrate 2 are connected to each other's external electrodes 3a as in the first to third embodiments. , 4a are directly overlapped to be in a conductive state, and the second electronic component 4 is also embedded in an insulating upper resin layer 41 laminated on the base substrate 2. A wiring pattern 42 is provided on the surface of the upper resin layer 41, and the first electronic component 3 and the second electronic component 4 are connected to the wiring pattern 42 via connection vias 43 provided in the upper resin layer 41. Yes.

  The manufacturing method of the component-embedded substrate 40 configured as described above will be briefly described. Steps until the second electronic component 4 is electrically connected to the first electronic component 3 embedded in the resin layer 6 of the base substrate 2. 2 is the same as (a) to (h) in FIG. 2, and thereafter, a thermoplastic resin film such as PEEK or PEI is laid on the base substrate 2 so as to cover the second electronic component 4, and this is heated and The upper resin layer 41 is formed by applying pressure. Next, the upper resin layer 41 is irradiated with laser light to form via holes reaching the external electrode 3a of the first electronic component 3 and the external electrode 4b on the upper surface side of the second electronic component 4, and then the inside of the via hole is included. Then, the connection via 43 is formed inside the via hole by performing copper plating or the like on the entire surface of the upper resin layer 41, and finally, the wiring pattern 42 is formed by etching the plating layer on the surface.

  In the component-embedded substrate 40 according to the fourth embodiment thus configured, the external electrode 3a of the first electronic component 3 embedded in the resin layer 6 of the lower base substrate 2 and the upper resin layer 41 of the upper layer are provided. Since the external electrode 4a of the second electronic component 4 embedded in the conductive layer is directly superimposed without being via a via hole and is in a conductive state, it is possible to eliminate the conduction failure due to the misalignment of the via hole, Since the distance from the surface of the upper resin layer 41 to the external electrode 3a of the first electronic component 3 is reduced by the amount corresponding to the omission of the via hole, drilling of the via hole and plating formation in the via hole can be easily performed.

  In addition, the first electronic component 3 and the second electronic component 4 are incorporated in the upper and lower layers of the multilayer substrate in a parallel posture, and the external electrode 4 a of the second electronic component 4 is connected to the external electrode 3 a of the first electronic component 3. Since they are in close contact with each other without being inclined, the reliability of the conduction between them can be made extremely stable, and the depth can be prevented from changing during the formation of the via hole.

  In the first to fourth embodiments, the chip resistor is exemplified as the first electronic component built in the base substrate 2 and the second electronic component conducted to the first electronic component. It is also possible to use other electronic parts having external electrodes such as a chip capacitor and an IC chip.

1, 20, 30, 40 Component-embedded substrate 2 Base substrate 2a Embedding hole 3 First electronic component 3a External electrode 4 Second electronic component 4a External electrode 5 Wiring pattern 6 Resin layer 7 Wiring material 8 Release plate 9 Fillet 41 Upper part Resin layer 42 Wiring pattern 43 Connection via

Claims (3)

In the component-embedded substrate in which the first electronic component having the external electrode is embedded in the base substrate and the second electronic component having the external electrode is mounted on the base substrate ,
Wherein is set to a larger area than the external electrode of the first said external electrode of the electronic component and the second electronic component, the Rukoto to conduct overlapping these two external electrodes each other directly, the first electronic component A component-embedded substrate characterized in that a part of the external electrode is exposed from an end surface of the second electronic component .   2. The built-in component according to claim 1, wherein an embedding hole is provided in the base substrate, and the first electronic component is embedded in a resin layer filled in the embedding hole. Mold substrate. 3. The second electronic component according to claim 1, wherein the second electronic component is fixed using the external electrode of the first electronic component fixed as a connection land and the wiring pattern on the base substrate as a connection land. A component-embedded substrate having an external electrode .