JP2019091940A - Circuit structure - Google Patents

Abstract

To provide a circuit structure that is less likely to generate disconnection of wiring caused by shape change of a resin molded body.SOLUTION: A circuit structure (1) comprises: an electronic component (3) having electrodes (31 and 32); a resin molded body (2) in which the electronic component 3 is buried; and wirings (41 and 42) connected with the electrodes (31 and 32). A groove (21) is formed around the electronic component (3) in the resin molded body (2). The wirings (41 and 42) are provided so as to pass in the groove (21).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a circuit structure having a resin molded body in which an electronic component is embedded.

  In recent years, there has been an increasing demand for realizing portable electronic devices, small sensors, or health devices (such as electronic thermometers and sphygmomanometers) as thin, lightweight, small, and highly water-resistant wearable products at low cost.

  Usually, such electronic devices are passive components (resistors, capacitors etc.), active components (LSI, IC etc.), power supply devices (battery etc.), display devices (LED etc.), and other electronic components (sensors, switches) Etc.) are built on a printed circuit board. Conventionally, such a printed circuit board is obtained by etching a copper foil laminated on a glass fiber reinforced epoxy resin plate (glass epoxy substrate) or a polyimide sheet (flexible printed substrate). It is manufactured by the method of forming a wiring circuit. Furthermore, other electronic components are mounted on the wiring circuit on the substrate by using a solder, a conductive adhesive, a metal wire or the like.

  However, in the conventional printed circuit board in which a wiring circuit is formed by etching a copper foil laminated on a glass epoxy substrate or a flexible printed circuit board, there is a problem that costs such as material cost and processing cost increase. Furthermore, the environmental impact of the waste liquid from the etching process is also large. In addition, even in the case of mounting an electronic component using a solder, a conductive adhesive, a metal wire or the like, there is a problem that the cost such as the material cost and the processing cost becomes expensive.

  Furthermore, in order to mount a plurality of electronic components on such a printed circuit board, it is necessary to provide a predetermined space or more between the electronic components, which causes a problem of increasing the size of the substrate. In addition, when a printed circuit board is attached to a structural component such as a resin case, a certain amount of space is required between the substrate and the structural component, so the thickness of the product may increase or the size reduction of the product may be limited. There is.

  As described above, in order to realize the thinness, miniaturization, and cost reduction of the electronic device, it is necessary to have a method of assembling an electronic component which does not require the use of the conventionally used printed circuit board.

  Heretofore, Patent Documents 1 to 3 disclose examples of techniques for realizing an electronic device which does not require such a printed circuit board. The outline of the technology disclosed in these documents is described below.

  Patent Document 1: An electronic circuit package in which electronic parts, circuit elements and the like are embedded in a molding resin so that the electrode surface is exposed, and a circuit pattern is formed by a wiring pattern molded in the molding resin.

  Patent Document 2: An exterior component of a portable electronic device, comprising: an exterior body; an electronic component embedded in a state in which an electrode is exposed on an inner side surface of the exterior body; and the electronic component disposed on the inner side surface And a circuit connected to the electrode of

  Patent Document 3: An electronic component mounting apparatus comprising: a housing at least a part of which is a resin molded product; and an electronic component mounted in the housing, wherein the electronic component is an electrode of the electronic component. An electronic component mounting apparatus, wherein the electronic component mounting apparatus is embedded in the resin molded product in a state in which is exposed, and a wire is electrically connected to the exposed electrode.

Japanese Patent Application Laid-Open No. 7-66570 (released on March 10, 1995) Unexamined-Japanese-Patent No. 2004-111502 (April 2004 release) Unexamined-Japanese-Patent No. 2010-272756 (disclosure on December 2, 2010)

  The problems that these conventional techniques have will be described below with reference to FIG. FIG. 6 is a diagram for explaining the problem of the prior art. FIG. 6A shows the configuration of a circuit structure 101 according to the prior art. The circuit structure 101 includes a resin molded body 102 made of resin, an electronic component 103, and wires 141 and 142. The electronic component 103 includes two electrodes 131 and 132 and is embedded in the resin molded body 102. The wiring 141 is connected to the electrode 131, and the wiring 142 is connected to the electrode 132. The wires 141 and 142 are both made of metal.

  In FIG. 6, (b) shows the occurrence of disconnection of the wires 141 and 142 in the circuit structure 101 according to the prior art. Generally, resin and metal have different coefficients of linear expansion. When shape change 151, 152 of expansion or contraction as shown in (b) of FIG. 6 occurs in the resin molded body 102, the crack 161 between the resin molded body 102 made of resin and the electrodes 131, 132 made of metal. 162 occurs. As a result, a disconnection occurs in a portion overlapping with the crack 161 in the wiring 141, and similarly, a disconnection also occurs in a portion overlapping the crack 162 in the wiring 142.

  The present invention has been made to solve the above-mentioned problems. An object of the present invention is to provide a circuit structure in which disconnection of wiring due to shape change is less likely to occur in a resin molded body.

  In order to solve the above problems, a circuit structure according to the present invention includes an electronic component having an electrode, a resin molded body in which the electronic component is embedded, and a wire connected to the electrode. A groove is formed around the electronic component in the resin molded body, and the wiring is provided so as to pass through the groove.

  According to the above configuration, even if the shape change of expansion or contraction occurs in the lower part of the wiring in the resin molded body, the shape of the groove changes to follow it. Therefore, the force generated by the shape change of the resin molded body is dispersed by the shape change of the groove, and the force does not concentrate on one point in the wiring. As a result, the occurrence of disconnection of the wiring can be made difficult to occur.

  In the circuit structure according to the present invention, the wiring is preferably provided to be filled in the groove.

  According to the above configuration, even if the shape change of expansion or contraction occurs in the lower part of the wiring in the resin molded body, the shape of the filling portion to the groove in the wiring follows the resin molding due to the malleability of the wiring material It changes following the shape change of the body. Therefore, the disconnection of the wiring due to the shape change of the resin molded body hardly occurs.

  In the circuit structure according to the present invention, it is preferable that a recess toward the bottom of the groove is formed at a position corresponding to the groove in the wiring.

  According to the above configuration, since the shape of the recess also changes in accordance with the change in shape of the resin molded body, disconnection of the wiring due to the change in shape of the resin molded body can be further prevented.

  The circuit structure according to aspect 4 of the present invention further includes at least one conductive layer provided between the wiring and the electronic component in the groove in any of the above aspects 1 to 3. preferable.

  According to the above configuration, even when direct connection between the wiring and the electrode is difficult, the wiring can be connected to the electrode without any problem via the conductive layer.

  In the manufacturing method according to the present invention, in order to solve the above-mentioned problems, when the electronic component having an electrode is disposed on a sheet on which an adhesive liquid layer is applied on the surface, the liquid layer is wetted. A step of forming a wetted portion around the part, a step of curing the wetted portion, and a step of injection molding a resin material on the surface of the sheet on which the electronic component is placed after the wetted portion is cured. And forming a resin molded body in which a groove corresponding to the wetted portion is disposed around the electronic component by peeling the wetted portion together with the sheet, and a wire connected to the electrode. And forming the groove so as to pass through the groove.

  According to the above configuration, it is possible to manufacture a circuit structure in which the disconnection of the wiring is less likely to occur due to the change in shape of the resin molded body.

  According to one aspect of the present invention, it is possible to provide a circuit structure in which disconnection of the wiring due to the shape change of the resin molded body is less likely to occur.

It is a figure which shows the principal part structure of the circuit structure which concerns on Embodiment 1 of this invention. It is a figure which shows the manufacturing method of the circuit structure which concerns on Embodiment 1 of this invention. It is a figure which shows the principal part structure of the circuit structure which concerns on Embodiment 2 of this invention. It is a figure which shows the manufacturing method of the circuit structure which concerns on Embodiment 2 of this invention. It is a figure which shows the principal part structure of the circuit structure which concerns on Embodiment 3 of this invention. It is a figure for demonstrating the subject of a prior art.

Embodiment 1
Embodiment 1 of the present invention will be described below based on FIGS. 1 and 2.

(Configuration of circuit structure 1)
FIG. 1 is a view showing the main configuration of a circuit structure 1 according to Embodiment 1 of the present invention. FIG. 1A is a top view of the circuit structure 1, and FIG. 1B is a side cross-sectional view of the circuit structure 1. As shown to (a) of FIG. 1, the circuit structure 1 is provided with the resin molding 2, the electronic component 3, and the wiring 41 and 42. As shown in FIG.

  The circuit structure 1 is a part incorporated in various devices such as a portable electronic device, a small sensor, or a health device (electronic thermometer, sphygmomanometer, etc.), and is a portion that carries out the main or auxiliary functions of the device. Since a plurality of electronic components 3 can be incorporated in the circuit structure 1, the size can be reduced as compared with the conventional printed circuit board-based circuit structure that achieves the same function. Thus, the circuit structure 1 contributes to realizing various devices into which the circuit structure 1 is incorporated as thin, lightweight, and compact wearable products.

  The resin molded body 2 is a resin base made of a resin material such as ABS resin (acrylonitrile butadiene styrene resin), and the electronic component 3 is disposed on the surface of the resin base 2 so as to be embedded therein.

  The electronic component 3 is a circuit element constituting one electronic circuit formed in the circuit structure 1. The electronic component 3 can be a passive component (for example, a resistor, a capacitor, etc.) or an active component (LSI, IC, etc.). The electronic component 3 is embedded at a certain distance from each end of the surface of the resin molded body 2. The electronic component 3 is provided with a pair of electrodes 31 and 32. A groove 21 having a predetermined width and depth is formed around the embedded portion of the electronic component 3 in the resin molded body 2. The width and depth of the groove 21 are appropriately determined in accordance with the type and size of the electronic component 3 and the resin molded body 2 constituting the circuit structure 1. One surface of the electrodes 31 and 32 is exposed from the resin molded body 2, and the electrodes 31 and 32 are connected to one end of the wires 41 and 42 on the exposed surfaces thereof.

  The wires 41 and 42 are formed on the embedded surface of the electronic component 3 in the resin molded body 2. The wires 41 and 42 are conductive wires made of various conductive materials (gold, silver, copper, etc.). In (b) of FIG. 1, the wiring 41 is formed on the resin molded body 2 so as to fill any portion of the groove 21 facing the electrode 31. On the other hand, the wiring 42 is formed on the resin molded body 2 so as to fill any portion of the groove 21 facing the electrode 32.

  In the present embodiment, the material of the wirings 41 and 42 is filled in the groove 21 at a position deeper than the position on the same surface as the surface of the resin molded body 2 without a gap. That is, the wires 41 and 42 are further formed on the resin molded body 2 without forming a gap between the surface of the groove 21 and the surface of the electrodes 31 and 32. As a result, the surfaces (exposed surfaces) of the wires 41 and 42 are uniformly flat regardless of whether or not the groove 21 is located below the wires 41 and 42. Furthermore, the thickness of the portion corresponding to the groove 21 in the wires 41 and 42 is larger than the thickness of the other portion in the wires 41 and 42 (the portion opposed to the surface without the groove 21 in the resin molded body 2).

  The other ends of the wires 41 and 42 are connected to the electrodes of another electronic component (not shown) in the circuit structure 1. Thus, the electronic component 3 is electrically and functionally connected to other electronic components.

  FIG. 1C shows the circuit structure 1 in a state in which the shape changes 51 and 52 of the resin molded body 2 occur. Even if the shape change 51 of expansion or contraction occurs due to some cause (thermal shock, change in ambient temperature, mechanical load, etc.) in the lower part of the wiring 41 in the resin molded body 2, the location filled in the groove 21 in the wiring 41 Due to the malleability of the material of the wire 41, the shape of the wire changes in accordance with the shape change 51 of the resin molded body 2. That is, the wiring 41 functions to absorb the force received by the shape change 51 in the resin molded body 2. For example, in (c) of FIG. 1, the shape change 51 is the expansion of the resin molded body 2, and the width of the groove 21 is expanded by this. At this time, since the filling portion of the wiring 41 in the groove 21 also spreads following the expansion, it is possible to prevent the occurrence of the disconnection of the wiring 41. Similarly, when the width of the groove 21 is expanded due to the shape change 52, the filling portion of the wiring 42 in the groove 21 is also expanded following the expansion, so it is possible to prevent the occurrence of disconnection of the wiring 42.

(Method of Manufacturing Circuit Structure 1)
FIG. 2 is a view showing a method of manufacturing the circuit structure 1 according to the first embodiment of the present invention. Hereinafter, a method of manufacturing the circuit structure 1 will be described with reference to this figure.

(Temporary fixing process)
As shown in FIG. 2A, first, a sheet 5 for temporarily fixing the electronic component 3 is prepared. As a material of the base sheet of the sheet 5, a material having transparency capable of transmitting ultraviolet light and flexibility to ensure the step of peeling described later is preferable, for example, PET ( Polyethylene terephthalate), PEN (polyethylene naphthalate), PPS (polyphenylene sulfide), etc. can be used. In the present embodiment, the sheet 5 is a PET sheet having a thickness of 50 μm.

  An adhesive liquid layer 6 is applied to one side of the sheet 5. As the liquid layer 6, one having a short curing time is preferable. For example, an ultraviolet curing adhesive can be used. The ultraviolet curing adhesive cures when it is irradiated with ultraviolet light, and bonds the substrate sheet and the electronic component. Therefore, when the ultraviolet ray is irradiated from the surface where the adhesive is applied, the electronic component itself becomes a barrier that inhibits the ultraviolet ray from being irradiated to the adhesive, and the curing (adhesion) may be insufficient. There is. Therefore, by using a material that transmits ultraviolet light to the substrate sheet and irradiating ultraviolet light from the surface of the substrate sheet to which the adhesive is not applied, the adhesive is sufficiently cured to ensure the electronic component in a short time. It can be fixed to a substrate sheet. In the present embodiment, the liquid layer 6 is a UV curable adhesive (GL-3005H manufactured by Kurabo Labs) having a thickness of 2 to 3 μm.

The electronic component 3 is aligned and disposed on the surface of the sheet 5 to which the liquid layer 6 is applied. Specifically, the electronic component 3 is disposed at a position corresponding to a position on the sheet 5 at a certain distance from each end of the surface of the resin molded body 2. At this time, as shown in (b) of FIG. 2, the liquid layer 6 wets the surface of the electronic component 3 due to the surface tension thereof, so that the wet-up portion 61 is formed around the electronic component 3. After the formation of the wet portion 61, ultraviolet light of 3000 mJ / cm ² is irradiated from the surface of the sheet 5 opposite to the surface on which the electronic component 3 is disposed. As a result, the electronic component 3 is adhered and fixed to the sheet 5 by curing of the liquid layer 6. At this time, the wet-up portion 61 is also cured and maintains its shape even after the irradiation of the ultraviolet light. The wet-up portion 61 functions as a core (mold) for forming the groove 21 in an injection process described later.

  The shape (width and height) of the wetted portion 61 is determined according to the surface tension of the liquid layer 6. If the surface tension of the liquid layer 6 is adjusted, it is possible to form the wet-up portion 61 of a desired height. As a result, the groove 21 of the resin molded body 2 to be formed in a later step can be made to have a desired depth.

(Injection process)
After temporarily fixing the electronic component 3 to the sheet 5, the sheet 5 is placed in a mold for manufacturing the circuit structure 1. This mold is a mold for injection molding the resin molded body 2 in which the electronic component 3 is embedded. The sheet 5 is disposed such that the surface on the back side of the surface of the sheet 5 to which the electronic components 3 are temporarily fixed is in contact with the corresponding surface of the mold. The sheet 5 is disposed at the formation position of the surface of the resin molded body 2 in the mold. In this state, a resin material such as ABS resin is injected under the conditions of a mold temperature of 80 ° C., an injection resin temperature of 180 ° C., and an injection pressure of 20 kg / cm ² . Thereby, the electronic component 3 is embedded in the resin molded body 2.

  It is preferable that a thermally conductive filler be pre-filled in the resin material. Thereby, the heat generated from the electronic component 3 at the time of injection molding can be easily released to the outside. The heat conductive filler may, for example, be a metal powder such as copper or an inorganic material powder such as aluminum nitride or aluminum oxide.

(Electrode exposure process)
By peeling the sheet 5 from the molded product obtained by the above-mentioned injection molding, the electrodes 31 and 32 of the electronic component 3 are exposed on the surface of the resin molded body 2. The wetted portion 61 formed in the temporary fixing step is also peeled off from the resin molded body 2 together with the sheet 5. As a result, the resin molded body 2 in which the groove 21 is disposed around the electronic component 3 is formed.

(Wiring formation process)
Finally, wires 41 and 42 for connecting the electrodes 31 and 32 exposed from the surface of the resin molded body 2 are formed on the surface. At that time, for example, a method (for example, inkjet printing) of spraying conductive silver nanoink, which is a material of the wires 41 and 42, is used. At the time of forming the wires 41 and 42, the jet nozzle of the ink jet head moves so as to pass over the groove 21. Thus, the interconnections 41 and 42 are formed to pass through the inside of the groove 21. More specifically, the wires 41 and 42 are formed so as to continuously cover the flat surface of the resin molded body 2 and the surface of the groove 21.

  In the present embodiment, the silver nano ink is jetted so that the wiring 41, 42 is filled in the portion of the groove 21 facing the electrodes 31, 32. This is performed by appropriately changing the ejection amount of silver nanoink per unit time according to the surface shape of the resin molded body 2. For example, the amount of jet of silver nanoink per unit time to the surface of the groove 21 in the resin molded body 2 may be greater than the amount of jet of silver nanoink per unit time to the flat surface of the resin mold 2 . When the formation of the wires 41 and 42 is completed, the circuit structure 1 in which the electronic component 3 is embedded is completed. Note that screen printing or silver plating may be used instead of ink jet printing.

  By the manufacturing method described above, it is possible to manufacture the circuit structure 1 in which the disconnection of the wirings 41 and 42 is less likely to occur due to the shape change of the resin molded body 2.

Second Embodiment
Embodiment 2 according to the present invention will be described below based on FIGS. 3 and 4. The same numerals are given to each member in common with Embodiment 1 mentioned above, and detailed explanation is omitted.

(Configuration of circuit structure 1a)
FIG. 3 is a view showing the main configuration of the circuit structure 1a according to the first embodiment of the present invention. (A) of FIG. 3 is a top view of the circuit structure 1a, and (b) is a side cross-sectional view of the circuit structure 1a. As illustrated in (a) of FIG. 3, the circuit structure 1 a includes the resin molded body 2, the electronic component 3, and the wires 41 and 42 as in the circuit structure 1 according to the first embodiment of the present invention. There is. However, the circuit structure 1a according to the present embodiment is different from the circuit structure 1 according to the first embodiment in that the recessed portions 43 and 44 are formed in the wirings 41 and 42.

  As shown in (b) of FIG. 3, a recess 43 having a certain depth is formed at the filling portion of the wiring 41 into the groove 21. Further, a recess 44 having a predetermined depth is formed at the filling portion of the wiring 42 into the groove 21. As described above, the exposed surfaces of the wires 41 and 42 are not uniformly flat, and have a shape in which they are recessed toward the bottom of the resin molded body 2 at the locations where the recessed portions 43 and 44 are formed. The recessed portions 43 and 44 can also be said to be other grooves formed at positions corresponding to the grooves 21 in the wires 41 and 42.

  (C) of FIG. 3 shows the circuit structure 1a in a state in which the shape changes 51 and 52 of the resin molded body 2 occur. Even if the shape change 51 of expansion or contraction occurs in the lower portion of the wiring 41 in the resin molded body 2, the portion filled in the groove 21 in the wiring 41 changes in shape in the same manner as in Embodiment 1, and The shape of the recessed portion 43 also changes following the shape change 51 of the resin molded body 2. For example, in (c) of FIG. 1, the shape change 51 is the expansion of the resin molded body 2, and the width of the groove 21 is expanded by this. At this time, since both the portion of the wiring 41 filled in the groove 21 and the recess 43 formed in the portion follow the expansion and both expand, the generation of the breakage of the wiring 41 is made further than in the first embodiment. It can be made hard to occur. Similarly, when the width of the groove 21 is expanded due to the shape change 52, both the filling portion of the wiring 42 in the groove 21 and the recess 44 formed in the portion follow the expansion and both expand. It is possible to make the occurrence of the disconnection of 42 even more difficult than in the first embodiment.

(Method of Manufacturing Circuit Structure 1a)
FIG. 4 is a view showing a method of manufacturing the circuit structure 1a according to the second embodiment of the present invention. Hereinafter, a method of manufacturing the circuit structure 1a will be described with reference to this figure.

  The temporary fixing step, the injection step, and the electrode exposing step in the present embodiment are the same as in the first embodiment, and thus the detailed description thereof is omitted. The wiring formation process has some differences from the first embodiment. In the present embodiment, in the wiring formation step, the silver nanoink is jetted so that the recessed portions 43 and 44 are formed at the filling portions of the wirings 41 and 42 in the grooves 21. This is performed, for example, by making the ejection amount of silver nanoink per unit time constant regardless of the surface shape of the resin molded body 2. For example, the ejection amount per unit time of the silver nanoink to the surface of the groove 21 in the resin molding 2 may be equal to the ejection amount per unit time of the silver nanoink to the flat surface in the resin molding 2. As a result, the wires 41 and 42 of uniform thickness are continuously formed from the flat surface of the resin molded body 2 on the curved surface at the formation position of the groove 21. As a result, the concave portions 43 and 44 are formed along the curved shape of the formation position of the groove 21 in the resin molded body 2.

  The shapes (width and depth) of the recessed portions 43 and 44 can be adjusted by adjusting the shape of the wetting part 61 (adjusting the amount of wetting) in the temporary fixing step. Furthermore, it can adjust also with the application quantity of the silver nanoink in a wiring formation process.

Third Embodiment
The third embodiment according to the present invention will be described below based on FIG. The same numerals are given to each member in common with Embodiment 1 or 2 mentioned above, and detailed explanation is omitted.

(Configuration of circuit structure 1b)
FIG. 5 is a view showing the main configuration of a circuit structure 1b according to a third embodiment of the present invention. (A) of FIG. 5 is a top view of the circuit structure 1b, and (b) is a side sectional view of the circuit structure 1b. As shown in (a) of FIG. 5, the circuit structure 1 b includes the resin molded body 2, the electronic component 3, and the wires 41 and 42 as in the circuit structure 1 a according to the second embodiment of the present invention. There is. Furthermore, as shown in (b) of FIG. 5, in the circuit structure 1b according to the present embodiment, as in the circuit structure 1a according to the second embodiment, the recessed portions 43 and 44 are formed in the wirings 41 and 42. It is done. However, the circuit structure 1 b according to the present embodiment is different from the circuit structure 1 a according to the second embodiment in that the circuit structure 1 b further includes the additional conductive layers 71 and 72.

  As shown in (b) of FIG. 5, the conductive layer 71 is formed between the wiring 41 and the electrode 31. On the other hand, the conductive layer 72 is formed between the wiring 42 and the electrode 32. Therefore, the wiring 41 is not in direct contact with the electrode 31, and the wiring 42 is not in direct contact with the electrode 32. The wires 41 and 42 are provided so as to continuously cover the exposed surfaces of the electrodes 31 and 32 and the surface facing the groove 21. In the present embodiment, the conductive layers 71 and 72 are formed to reach the bottom of the groove 21, but the invention is not necessarily limited to this.

  After the formation of the conductive layers 71 and 72, the wirings 41 and 42 are formed. The conductive layers 71 and 72 can be formed by the same method as the method for forming the wirings 41 and 42. For example, when the wirings 41 and 42 are formed by inkjet, the conductive layers 71 and 72 are similarly formed by inkjet. Thereby, since it is not necessary to use another method for forming the conductive layers 71 and 72, the manufacturing cost of the circuit structure 1b can be further suppressed.

  The material of the conductive layers 71 and 72 may be arbitrary as long as it is conductive. An optimal material may be selected and used to form the conductive layers 71 and 72 in accordance with the shapes, sizes, or types of materials of other components of the circuit structure 1b. For example, there are various possible materials for forming the conductive layers 71 and 72 as follows.

  (1) When there is a possibility that the wires 41 and 42 may be disconnected at the bottom of the groove 21 due to the insufficient supply of materials (silver nanoink etc.) of the wires 41 and 42 because the grooves 21 are deep, the manufacturing of the conductive layers 71 and 72 The same material as that of the wirings 41 and 42 may be used. As a result, even if disconnection of the wires 41 and 42 occurs at the bottom of the groove 21 when the wires 41 and 42 are formed, the wires 41 and 42 can be formed through the electrodes 31 and 32 via the conductive layers 71 and 72 formed in advance. Can be connected to.

  (2) In the case where there is a risk that the connection between the wires 41 and 42 and the electrodes 31 and 32 will be insufficient because the material of the wires 41 and 42 has poor wettability with the electrodes 31 and 32, the conductive layers 71 and 72 For the material of (1), a material (alcohol-based material, water-based material, etc.) having different characteristics from the material of the wirings 41 and 42 may be used. This can eliminate the insufficient bonding.

  (3) When there is a possibility that a rise in connection resistance may occur between the material of the interconnections 41 and 42 and the material of the electrodes 31 and 32 due to, e.g., rubanic corrosion, such a rise in the material of the conductive layers 71 and 72 Use materials that can reduce For example, if the material of the wires 41 and 42 is silver nanoink and the electronic component 3 is made of tin, copper may be used as the material of the conductive layers 71 and 72. This can suppress an increase in connection resistance.

  In addition to the conductive layers 71 and 72, another conductive layer may be formed in the groove. For example, a conductive layer 71 made of gold may be formed on the electrode 31, another conductive layer made of silver may be formed thereon, and a wire 41 may be further formed thereon. As described above, at least one conductive layer may be formed between the wirings 41 and 42 and the electrodes 31 and 32.

  After the formation of the wires 41 and 42, a protective resist (not shown) is preferably formed on the embedded surface of the electronic component 3 in the resin molded body 2 so as to at least cover the wires 41 and 42 and the conductive layers 71 and 72. . Thus, at least the wirings 41 and 42 and the conductive layers 71 and 72 are shielded from the external environment, and therefore, the wirings 41 and 42 and the conductive layers 71 and 72 can be protected from external adverse factors (such as moisture and humidity). .

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as a circuit structure incorporated in various devices such as portable electronic devices, small sensors, or health devices (such as electronic thermometers and blood pressure monitors).

1, 1a, 1b Circuit Structure 2 Molded Resin 3 Electronic Component 5 Sheet 6 Liquid Layer 31, 32 Electrode 41, 42 Wiring 71, 72 Conductive Layer

Claims (4)

A circuit structure having an electronic component having an electrode, a resin molded body in which the electronic component is embedded, and a wire connected to the electrode,
A groove is formed around the electronic component in the resin molded body, and the wiring is provided to pass through the groove,
The circuit structure characterized in that a surface of the resin molded body on which the wiring is provided and at least a part of the electrode are in substantially the same plane.   The circuit structure according to claim 1, wherein the wiring is provided to be filled in the groove.   The circuit structure according to claim 1, wherein a recess toward the bottom of the groove is formed at a position corresponding to the groove in the wiring.   The circuit structure according to any one of claims 1 to 3, further comprising at least one conductive layer provided between the wiring and the electronic component in the groove.

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