JP4954778B2 - Three-dimensional electronic circuit device and connecting member - Google Patents

Description

  The present invention relates to a three-dimensional electronic circuit device configured by three-dimensionally stacking circuit boards on which electronic components are mounted, and a connection member that is a component of the circuit board and connects the circuit boards.

  In recent years, there has been a strong demand for mobile products typified by mobile phone devices to have high functions such as a camera and a built-in TV and high added value such as lightness, thinness, and smallness. In order to satisfy such demands, it is indispensable to reduce the size of the component parts, increase the mounting density, and enhance the functionality of the circuit board. In order to achieve high-density mounting, attention has been focused on three-dimensional mounting technology that configures a three-dimensional electronic circuit device by three-dimensionally stacking (multi-stage mounting) circuit boards on which components are arranged on the component mounting surface. ing.

  As an application example of the three-dimensional mounting technology, three-dimensionalization is achieved by superimposing a plurality of independent single temporary packages made of semiconductor chips using a three-dimensional package in which bare chips are stacked (for example, a stack type CSP). The thing using a package lamination three-dimensional apparatus is mentioned. Furthermore, there is a technique for realizing high-density mounting of electronic components by connecting circuit boards on which electronic components (semiconductor chips, passive components, etc.) are mounted in multiple stages.

  Patent Document 1 proposes a technique for mechanically connecting a plurality of stacked circuit boards with a conductive material through via holes as an example of multistage mounting. Since this technique can minimize the length of electrical wiring between circuit boards, it is useful for three-dimensional electronic circuit devices for applications that require high-frequency characteristics.

  Patent Document 2 proposes a technique for mechanically connecting a plurality of superimposed circuit boards via conductive spacers as a further example of multistage mounting. Specifically, an electrode is provided on a component mounting surface in the vicinity of the outer end portion of the circuit board, and a spacer is soldered to and connected to the electrode of the opposite circuit board. This technique has an advantage that positioning of a plurality of circuit boards and spacers is easy.

  Patent Document 3 proposes a technique for mechanically connecting a main circuit board and a sub circuit board with pin-shaped connection electrodes. Specifically, the main circuit board has electronic parts mounted thereon and a plurality of through holes for external connection extending in a direction substantially perpendicular to the component mounting surface. The sub circuit board has a plurality of pin-like electrodes and end face electrodes that fit into the through holes of the main circuit board. The main circuit board and the sub circuit board are connected by soldering in a state where the pin-like connection and the through hole are fitted to each other.

In Patent Document 4, a plurality of electrodes connected by wiring on the surface or inner layer of a plurality of circuit boards are arranged in the peripheral portions of the respective substrates, and leads are arranged on the electrodes arranged in the peripheral portions (hereinafter referred to as end face electrodes). A technique for mechanically connecting the frames with a conductive material has been proposed. The lead frame is provided with a plurality of leads each corresponding to one electrode. Each end face electrode is formed in a concave shape at the end of the circuit board so as to accommodate the corresponding lead. That is, a plurality of circuit boards are connected by soldering in a state where the leads are accommodated in the corresponding concave end face electrodes.
Japanese Patent Laid-Open No. 11-220262 JP 2005-217348 A JP-A-4-262376 JP-A-1-226192

  However, each of the above techniques has the following problems. First, regarding the technique of Patent Document 1, even if it is found that the completed three-dimensional circuit device has a defect, analysis of the cause of the defect (identification of the electronic component causing the defect), replacement of the electronic component causing the defect, etc. Cannot be repaired. In other words, in the completed three-dimensional circuit device, each circuit board is mechanically connected to each other with a conductive material via via holes, and electronic components and wiring are confined in the circuit board (three-dimensional circuit device). Yes.

  Therefore, it is very difficult to remove each circuit board from the three-dimensional circuit device in order to correct or repair the cause of the failure, and the other circuit boards are easily destroyed when removed. Furthermore, since a plurality of circuit boards are connected through a plurality of via holes arranged at several positions on the circuit board mounting surface, a difficult operation of positioning the plurality of circuit boards and the plurality of via holes is required. . In addition, the mounting area of the circuit board is damaged by the via hole.

  Regarding the technique of Patent Document 2, since the electrodes and spacers provided in specific regions on the mounting surfaces of the plurality of circuit boards are soldered, the difficulty in positioning the circuit boards and spacers is alleviated. However, the problem when the three-dimensional circuit device after completion is found to be defective and the mounting area of the circuit board being damaged by the spacer are the same as in the technique of Patent Document 1.

  With regard to the technology of Patent Document 3, a plurality of pin-shaped electrodes are fitted into a plurality of through holes corresponding to the electrodes and soldered, so that a main circuit board (through hole) and a sub circuit board are used. Accuracy is required for positioning of the (pin-shaped electrode). Furthermore, since the through holes and the pin-like electrodes each require a predetermined interval, the mounting area of the main circuit board and the sub circuit board is impaired. Since the pin-shaped electrode and the through hole are soldered, the problem when the completed three-dimensional circuit device is found to be defective is the same as in the technique of Patent Document 1.

  Regarding the technique of Patent Document 4, since the lead frame is mechanically connected to the end face electrode with a conductive material, it is possible to prevent the mounting area of the circuit board from being damaged. However, inconvenience arises when the mounting density per unit area of the circuit board increases. That is, as the mounting density on the mounting surface of the circuit board increases, the number of end face electrodes per unit area also increases.

  In order to absorb the increase in the number of end face electrodes per unit area, the pitch of the end face electrodes and the pitch of the leads must be narrowed, and the end face electrodes and the leads themselves must be narrowed. The end face electrode and the lead each require a predetermined interval, similar to the relationship between the through hole and the pin electrode in Patent Document 3 described above. Therefore, it is very difficult to narrow the individual end face electrodes and leads and narrow the pitch.

  In addition, narrowing and narrowing of the end face electrodes and leads according to an increase in mounting density first leads to a reduction in lead strength. In addition, the strength of the three-dimensional electronic circuit device connected by the leads is reduced, and an electrical connection failure between the circuit boards due to the leads is also caused. The problem caused by the increase in the mounting density is common to the techniques of Patent Document 1, Patent Document 2, and Patent Document 3.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a three-dimensional electronic circuit device that can easily cope with the narrowing of the pitch of electrodes and that can realize a good electrical connection between the electrodes.

In order to achieve the above object, a three-dimensional electronic circuit device according to the present invention electrically connects a plurality of circuit boards on which electronic components are mounted, arranged in multiple layers so that the principal surfaces overlap each other at their end faces. In the connected three-dimensional circuit device, the end face of each circuit board has a plurality of end face electrodes arranged at a first pitch interval, and the end face electrodes of the respective circuit boards are arranged in the multilayer direction. The connecting member includes an anisotropic conductive member that connects surfaces of the end face electrodes and a sheet-like member that is in contact with the anisotropic conductive member. The anisotropic conductive member having a plurality of conductive wires extending in the multilayer direction intermittently arranged at a second pitch interval narrower than the first pitch interval on the surface of the sheet-like member. And at least one of the conductors is in contact It is a three-dimensional circuit device.

  Here, the predetermined cross-sectional shape is preferably defined by a curve or a straight line, and more preferably a substantially arc shape. The sheet-like member preferably has a plurality of grooves formed on a different surface from the surface on which the conducting wire is disposed, and the groove is formed in parallel with the direction in which the conducting wire extends. preferable. In addition, the groove | channel should just be either a polygon or a circular arc in the cross-sectional shape.

  The grooves are preferably formed at a predetermined pitch in a direction orthogonal to the direction in which the conducting wires extend, and the grooves are preferably disposed between the plurality of conducting wires.

  Moreover, the groove | channel may be formed in parallel with the said conducting wire between the said several conducting wires among the surfaces where the said conducting wire of the said sheet-like member was distribute | arranged. The sheet-like member is composed of first and second members having different longitudinal elastic modulus, and the longitudinal elastic modulus of the first member in which the conducting wire is arranged is that of the second member in which the conducting wire is not arranged. It may be smaller than the longitudinal elastic modulus.

  Further, the connecting member of the present invention that achieves the above object is a sheet-like member having a property that an anisotropic conductive member and a plurality of conductive wires are arranged in parallel at a predetermined pitch and are easily curved toward one surface side. And are laminated.

  If the connecting member of the present invention is used, it is possible to easily cope with a narrow pitch of the end face electrodes, and the mounting area is not increased. Further, even when the substrate is deformed or warped, any one of the plurality of conductors is electrically connected to the end surface electrode, so that electrical connection between the end surface electrodes of the first and second circuit boards is achieved. Can be secured.

  If these techniques are used, it is possible to configure a three-dimensional electronic circuit device by connecting electrodes extending to the periphery of a circuit board that is guaranteed to be non-defective by individual inspection before connection. Even if a failure occurs, removing the connecting member in contact with the electrode from the circuit board enables repair work such as analysis of the cause of the failure (identification of the electronic component causing the failure) or replacement of the electronic component causing the failure. Is possible. Furthermore, even when a circuit board becomes a waste product because it cannot be repaired, it is only necessary to replace the circuit board, which has a great merit in development efficiency.

  In addition, even when the number and dimensions of the end electrodes on the circuit board are different, standardizing a sheet-like member with a conductor having a finer pitch than the pitch of the end electrodes according to the number and dimensions of the end electrodes. This can be flexibly handled by cutting out the sheet-like member.

  Moreover, since the sheet-like member in the position facing the end face electrode among the connecting members is curved corresponding to the shape of the end face electrode, a good gap between the end face electrode and the conductive wire is obtained via the anisotropic conductive member. A conduction state can be secured, and the reliability of electrical connection between the substrates is improved. Furthermore, since the sheet-like member is curved, the mechanical strength is increased, and there is an advantage that the sheet-like member is not easily deformed by an external force.

(Embodiment 1)
The configuration of the three-dimensional electronic circuit device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1A shows a plan view of the three-dimensional electronic circuit device according to the present embodiment, and FIG. 1B shows a cross-sectional view taken along line Ib-Ib in FIG. FIG. 2A shows an enlarged view of the Aa portion in FIG. 1A, and FIG. 2B shows a cross-sectional view taken along the line IIb-IIb in FIG. 2A.

  As shown in FIG. 1, the three-dimensional electronic circuit device 100 includes a first circuit board 111 disposed on the upper side, a second circuit board 112 disposed on the lower side, and a connecting member 120a. As shown in FIG. 1B, the first circuit board 111 includes a first surface MS on which an electronic component is mounted, a second surface BS facing the first surface MS, and the first surface MS. The substrate is defined by a third surface PS that is connected to each of the surface MS and the second surface BS at predetermined angles α and β. In the present embodiment, the angle α and the angle β are set to 90 degrees. The second circuit board 112 has the same configuration as the first circuit board 111.

  Further, the first circuit board 111 and the second circuit board 112 are held at an interval S by four plate-like connecting members 120a connected to the outer end face PS so that the respective mounting surfaces face each other. ing.

As the first circuit board 111 and the second circuit board 112, a double-sided wiring board or a multilayer wiring board is used. A semiconductor chip 113 and an electronic component 114 are mounted on the first circuit board 111, and a bare chip 116 and an electronic component 114 are mounted on the second circuit board 112. The electrodes of the semiconductor chip 113, the electronic component 114, and the bare chip 116 are connected to the wiring patterns and the electric electrodes corresponding to the respective electrodes provided on the first circuit board 111 and the second circuit board 112 by solder or conductive adhesive. Connected.

Here, the semiconductor chip 113 is a semiconductor element such as an IC or an LSI. The electronic component 114 is a general passive component such as a resistor, a capacitor, an inductor, a varistor, or a diode. Incidentally, the bare chip 1 16 is mounted in flip-chip mounting or wire bonding connection is also possible.

  As the first circuit board 111 and the second circuit board 112, a general resin substrate or an inorganic substrate can be used. In particular, a glass epoxy substrate, a substrate using an aramid base material, a build-up substrate, a glass ceramic substrate, or an alumina substrate is preferable.

  As shown in FIGS. 2A and 2B, the peripheral surfaces of the first circuit board 111 and the second circuit board 112 have a substantially arc-shaped cross section, and the arrangement direction of the circuit boards 111 and 112, that is, FIG. A plurality of end face electrodes 115 extending in the arrow Z direction are provided. This end face electrode 115 is connected to a wiring pattern 117 for power supply and electric signal formed on the surface of the wiring substrate 111.

  Here, a method of forming the end face electrode 115 will be described. First, through holes are formed in the peripheral portions of the first circuit board 111 and the second circuit board 112 by a metal layer such as copper by electroless plating. Alternatively, a via hole is formed by electroless plating or filling with a conductive material. Subsequently, a part of the formed through hole or via hole is cut with a mechanical cutting means together with the substrate end face. In this way, a substantially arc-shaped end face electrode 115 is formed. In addition to the above method, there is a method of forming the end face electrode 115 directly on the edge of the substrate by electroless plating, printing of a conductive material, etching, or the like.

  As shown in FIG. 2, the connecting member 120 a is configured by laminating a sheet-like member 121 a in which a plurality of fine metal wires 122 are arranged on one side and an anisotropic conductive film 123. The sheet-like member 121a is a flexible resin film such as polyester, polyimide, or aramid. The strength of the connecting member 120a mainly depends on the mechanical strength of the sheet-like member 121a. The sheet-like member 121a maintains the distance S between the substrates when the circuit boards 111 and 112 are connected by the connecting member 120a, and the circuit board 111 is applied to the circuit board 112 when a horizontal external force is applied to the connecting member 120a. Must be strong enough not to be displaced to the left or right.

  A plurality of fine metal wires 122 extending in the arrangement direction of the first circuit board 111 and the second circuit board 112 (arrow Z direction) are formed on one surface of the sheet-like member 121a. The plurality of fine metal wires 122 are formed at a predetermined pitch along the arrow X direction in the drawing. The method for forming the fine metal wires 122 having a predetermined pitch on the sheet-like member 121a is the same as the method for forming the wiring pattern on the flexible printed circuit board, and thus the description thereof is omitted here. The thin metal wire 122 is not necessarily limited to a metal lead wire as long as it has electrical conductivity, and may be an inorganic or organic conductor film processed by etching or the like.

As described above, by forming the end face electrode 115 in a substantially arc shape, the contact area with the fine metal wire 122 through the anisotropic conductive film 123 is increased as compared with the straight end face electrode, and a good conduction state is obtained. realizable. Further, when the sheet-like member 121a is curved and enters the semicircular gap of the end face electrode 115, the sheet form member 121a is not easily detached from the end face electrode 115, and is not easily deformed by an external force, thereby increasing the mechanical strength. As described above, the cross-sectional shape of the end surface electrode 115 that can increase the contact area and the mechanical strength between the sheet-like member 121a and the end surface electrode 115 is preferably an arc shape, but an arbitrary curve. It can also be defined in and straight line combinations.

  3A and 3B are a plan view and a cross-sectional view of a part of the sheet-like member 121a cut out in a square shape. FIG. 3A is a plan view of a surface where the fine metal wires 122 are not provided. Grooves 124a having a triangular cross section are formed at a predetermined pitch on the surface of the sheet-like member 121a opposite to the surface on which the fine metal wires 122 are formed. Since the sheet-like member 121 a is easily bent by the groove 124 a, the sheet-like member 121 a is likely to enter the semicircular gap of the end face electrode 115 when the connecting member 120 a is connected to the end face electrode 115. Further, the sheet-like member 121a is curved along the substantially arc shape of the end face electrode 115, and the electrical connection between the end face electrode 115 and the metal thin wire 122 through the anisotropic conductive film 123 is ensured. To be done. A method of inserting the sheet-like member 121a into the semicircular gap of the end face electrode 115 will be described in detail later.

  The anisotropic conductive film 123 is obtained by dispersing conductive particles in a thermosetting insulating resin, specifically, a film-like epoxy resin. In the anisotropic conductive film 123, the interval between the conductive particles is narrowed by pressure from the outside, and a conductive state is obtained by bringing the conductive particles into contact with each other. Therefore, the insulation state is maintained in the direction in which no pressure is applied.

  Next, with reference to FIG. 2 and FIG. 4, a process of connecting the first circuit board 1111 and the second circuit board 112 with a predetermined interval S through the connecting member 120a will be described. 4A and 4B correspond to the plan view of FIG. 2A and the cross-sectional view of FIG. 2B, and the sheet-like member 121a and the anisotropic conductive film constituting the connecting member 120a. 123 shows a state before 123 is connected to the end face electrode 115.

  When connecting the connecting member 120a to the end face electrode 115, first, using a jig (not shown), the mounting surfaces of the first circuit board 111 and the second circuit board 112 are lined up and down, and predetermined. The interval S is held apart.

  Next, as shown in FIGS. 4A and 4B, the anisotropic conductive film 123 and the fine metal wire 122 are arranged so as to be parallel to the end surfaces of the first circuit board 111 and the second circuit board 112. The arranged sheet-like members 121a are arranged side by side.

  Next, the sheet-like member 121a is crimped to the end surface of the circuit board 111 with the anisotropic conductive film 123 using a crimping tool (not shown). The crimping tool is provided with a protrusion or protrusion having a semicircular cross section at a position facing the end face electrode 115 so that the sheet-like member 121 enters the semicircular gap of the terminal electrode 115 reliably.

  In this state, when the anisotropic conductive film 123 is heated with a heating tool (not shown), the anisotropic conductive film 123 having a thermosetting resin as a base material is cured. By curing the anisotropic conductive film 123, the end face of the circuit board 111 including the end face electrode 115 and the metal thin wire 122 and the sheet-like member 121 are bonded. As a result, the connecting member 120a is firmly connected to the first circuit board 111 and the second circuit board 112 in the state shown in FIGS. In addition, the anisotropic conductive film 123 is heat-cured in a pressurized state, so that conduction between the end face electrode 115 and the metal thin wire 122 is ensured.

  Through the pressurizing / heating process described above, as shown in FIGS. 1 and 2, the first circuit board 111 and the second circuit board 112 are connected via the connecting member 120a. The end face electrodes 115 at the opposing positions of the first circuit board 111 and the second circuit board 112 are electrically connected to each other through the anisotropic conductive film 123 and the thin metal wire 122 which are brought into conduction by being pressurized and heated and cured. Connected. On the other hand, since the anisotropic conductive film 123 maintains an insulation state in the arrow X direction, the end face electrodes 115 arranged at a predetermined pitch are electrically insulated.

  In this way, by using a crimping tool having protrusions or protrusions corresponding to the shape of the end face electrode 115, the anisotropic conductive film 123 is heated and cured with an appropriate pressure applied to face the end face electrode 115. It is possible to secure a conduction state between the thin metal wires 122 to be performed. As shown in FIG. 2A, the end face electrode 115 is connected to a plurality of fine metal wires 122 (four in the figure) through the anisotropic conductive film 123. Therefore, the end face electrode 115 of the circuit board 111 and the end face electrode 115 of the circuit board 112 are electrically connected via the anisotropic conductive film 123 and the plurality of fine metal wires 122. As a result, good electrical connection between the first and second circuit boards 111 and 112 can be realized.

  Next, the conditions that the fine metal wire 122 should have will be described. The fine metal wires 122 are formed on the surface of the sheet-like member 121a with a pitch smaller than the pitch of the end face electrodes 115. Here, the pitch of the arrangement of the thin metal wires 122 is P (see FIG. 2A). In order to realize electrical connection between the end face electrodes 115 of the circuit boards 111 and 112, each end face electrode 115 only needs to be connected to at least one thin metal wire 122. However, considering the possibility of disconnection or peeling of the fine metal wires 122 during the pressurization / heating process or the risk of excessive energization per metal fine wire 122, each end face electrode 115 has two or more metal electrodes. It is preferable to be connected to the thin wire 122. For this reason, the pitch P is the length L of the arc of the end face electrode 115 (in the drawing, for convenience of description, the arrow is displayed outside the end face electrode, but actually indicates the length on the inner peripheral side of the end face electrode) It is preferable to make it less than 1/2 of this. In addition, since the anisotropic conductive film 123 is interposed between the fine metal wire 122 and the end face electrode 115, the pitch P of the fine metal wire 122 takes into consideration the thickness of the anisotropic conductive film 123 and the above conditions. It is necessary to make it smaller.

  In addition, since the amount of current that can be flowed varies depending on the thickness of the thin metal wire 122, the thickness of the thin metal wire 122 and the pitch of the array need to be set according to the required energization amount. In the case of the present embodiment, the pitch of the end face electrodes 115 is 700 μm, and the width of the end face electrodes 115 is 500 μm. Further, the fine metal wires 122 are formed by patterning on a sheet-like member 121a made of a flexible resin film and having a width of 20 μm and an arrangement pitch of 45 μm and having a thickness of about 25 μm.

  In the present embodiment, the groove 124a is provided on the back side of the sheet-like member 121a to facilitate bending. For this reason, when the sheet-like member 121a is crimped with a crimping tool, the sheet-like member 121a is bent in a shape corresponding to the arc of the end face electrode 115 by being deformed in the direction of narrowing the groove, and the end face electrode 115 and the sheet-like member 121a. The adhesion between them becomes stronger. The degree of curvature of the sheet-like member 121a can be controlled by changing the cross-sectional shape, size, and pitch of the groove 124a.

  Note that the sheet-like member 121 can be easily bent by reducing the thickness of the sheet-like member 121. However, the sheet-like member 121 also has a function of mechanically supporting the fine metal wires 122. If the thickness is too thin, the mechanical strength is lowered and the fine metal wires 122 cannot be properly supported.

  As described above, in the present embodiment, the same function as that of a conventional lead frame is realized by using the sheet-like member 121a on which the fine metal wires 122 are arranged and the connecting member 120a including the anisotropic conductive film 123. Yes. When it is desired to narrow the pitch between the end face electrodes 115, the lead frame has a limited response due to processing and strength problems, but the connecting member 120a of the present embodiment can reduce the pitch of the metal thin wires 122. It can be easily handled.

  Next, a case where the connecting member 120a is removed from the circuit boards 111 and 112 will be described. Since the anisotropic conductive film 123 has the property of being easily peeled off as compared with solder or the like, the sheet-like member 121a can be separated from the circuit boards 111 and 112 by strongly pulling the sheet-like member 121a. Accordingly, when a failure occurs in the circuit boards 111 and 112, the connection member 120a is peeled off from the circuit boards 111 and 112, and the cause analysis (identification of the electronic component causing the failure) or the electronic cause of the failure is performed for each circuit board. Repair work such as parts replacement is possible. Furthermore, even when a circuit board becomes a waste product because it cannot be repaired, only the circuit board can be replaced.

  In the present embodiment, a groove having a triangular cross section is provided on the surface of the sheet-like member 121a opposite to the surface on which the fine metal wires 122 are formed. However, the cross-sectional shape of the groove is not limited to this, and may be any other shape as long as the same effect can be exhibited. For example, as shown in FIGS. 5A and 5B, a polygonal groove such as a square (124a-1) or a trapezoid (124a-2) or a semicircular groove (124a-3) as shown in FIGS. You may use the formed sheet-like member (121a-1, 121a-2). Further, as shown in FIG. 5B, grooves having different cross-sectional shapes may be mixed.

  Also, the shape of the groove is not limited to the slit-shaped groove as shown in FIG. 3 but can be variously modified within a range where the same effect can be exhibited. 6A to 6C are plan views of the surfaces of the sheet-like members 121a-3 to 121a-5 that do not have the fine metal wires 122. FIG. 6 (a) to 6 (c) are obtained by cutting out a part of the sheet-like member into a quadrangular shape as in FIG. 3 (a). As shown in FIGS. 6A, 6B, and 6C, a groove (124a-4), a lattice-like groove (124a-5), a circular groove having rectangular recesses arranged at equal intervals in the Y direction, A plurality of holes (124a-6) interspersed with holes may be used. The groove 124a-4 in which rectangular concave portions are arranged at equal intervals and the groove 124a-6 in which a plurality of circular holes are dotted are more resistant to bending than the slit-shaped grooves. Further, the lattice-like groove 124a-5 has an advantage that the degree of curvature is uniform compared to the slit-like groove.

  In this embodiment, the conductive state between the end face electrode 115 and the thin metal wire 122 is secured using the anisotropic conductive film 123, but an anisotropic conductive paste may be used instead of the anisotropic conductive film. Similar effects can be obtained.

  In this embodiment, a substantially arc-shaped electrode is used as the end face electrode 115. However, the present invention is not limited to this. For example, a solder ball or a metal on a cylinder is inserted in the semicircular gap of the end face electrode 115. A connecting member may be connected to the outside of the connector. However, in this case, it is necessary to change the surface of the sheet-like member 121a that is easily curved to a surface opposite to that of the present embodiment. Therefore, it is necessary to determine the surface on which the groove 124 is provided and the cross-sectional shape of the groove. There is.

  In the present embodiment, the mechanical strength may be increased by filling a space formed between the first circuit board 111 and the second circuit board 112 with an insulating material. As the insulating material, a compound containing an inorganic filler and a thermosetting resin can be generally used.

  Further, in the present embodiment, an example in which two circuit boards are arranged so that the board surfaces face each other has been described, but it goes without saying that three or more circuit boards can be connected using the connecting member 120a. Absent.

(Embodiment 2)
In FIG. 7, the principal part top view of the three-dimensional electronic circuit device which concerns on Embodiment 2 of this invention is shown. The Ab portion in FIG. 7 corresponds to the Aa portion in FIG. FIG. 9A shows a partial cross-sectional view of the sheet-like member 121b used in the present embodiment. In the figure, parts having the same functions as those in FIG. 1 and FIG. The same shall apply thereafter.

  In the present embodiment, the connecting member 120a used in the first embodiment is replaced with a connecting member 120b. As shown in FIG. 9A, the sheet-like member 121b constituting the connecting member 120b has a groove 124b on the slit formed on the surface on which the metal electrode 122 is disposed. In the case of the first embodiment, the sheet-like member 121a is bent by being deformed in the direction in which the groove 124a is narrowed in the sheet-like member 121a. On the other hand, in the present embodiment, the sheet-like member 121b is curved by being deformed in the direction in which the groove 124b of the sheet-like member 121b is expanded. By using the sheet-like member 121b, the same effect as the sheet-like member 121a of the first embodiment can be obtained.

  In addition, since the method demonstrated in Embodiment 1 can be used for the method of adhere | attaching the connection member 120b on the circuit boards 111 and 112, description is abbreviate | omitted here.

(Embodiment 3)
FIG. 8 shows a plan view of the main part of a three-dimensional electronic circuit device according to Embodiment 3 of the present invention. The Ac portion in FIG. 8 corresponds to the Aa portion in FIG. FIG. 9B shows a partial cross-sectional view of the sheet-like member 121c used in the present embodiment.

  In the present embodiment, the connecting member 120a used in the first embodiment is replaced with a connecting member 120c. As shown in FIG. 9B, the sheet-like member 121c constituting the connecting member 120c has slit-like grooves 124c-1 and 124c-2 on both the surface on which the metal electrode 122 is disposed and the opposite surface. Is formed. In the present embodiment, the sheet-like member 121c is bent by being deformed in a direction in which the groove 124c-1 is narrowed and in a direction in which the groove 124c-2 is expanded. Therefore, the sheet-like member 121c has a property that it is more easily bent than the above-described sheet-like members 121a and 121b when an external force is applied.

  In addition, since the method demonstrated in Embodiment 1 can be used for the method of adhere | attaching the connection member 120c on the circuit boards 111 and 112 similarly to Embodiment 2, description is abbreviate | omitted here.

(Embodiment 4)
FIG. 10 shows a partial cross-sectional view of a sheet-like member 121d used in the three-dimensional electronic circuit device according to Embodiment 4 of the present invention. In the first embodiment described above, a groove is provided on the surface opposite to the surface having the metal electrode 122 of the sheet-like member 121a, thereby adding the property of being easily curved on one surface side. On the other hand, in this embodiment, the sheet-like member 121d has a two-layer structure of first and second members 125 and 126 having different longitudinal elastic coefficients. That is, the second member 126 has a property of being easily bent by increasing the longitudinal elastic modulus of the second member 126 to be larger than that of the first member 125 having the metal electrode 122 on the surface. is doing.

  Specifically, the second member 126 made of copper foil is bonded to the outside of the first member 125 made of polyimide resin film. Since the longitudinal elastic modulus of the copper foil is larger than the elastic modulus of polyimide, the copper foil is easily bent toward the copper foil side. By using the sheet-like member 121d having the configuration shown in FIG. 6 instead of the sheet-like member 121a shown in FIGS. 1 and 2, the same effect as in the first embodiment can be obtained.

  Furthermore, in the present embodiment, the second member 126 made of copper foil functions as a shield electrode or a shield layer, which is effective as a countermeasure against unnecessary radiation noise.

  As described above, the best mode for carrying out the present invention has been described with reference to the drawings. However, the scope of the present invention is not limited to this, and modes that can be easily reached by those skilled in the art are also included. It is clear that it belongs to the scope of the present invention.

  The three-dimensional electronic circuit device of the present invention can be applied to various mobile devices that require high functionality, multiple functions, and downsizing.

The top view and sectional drawing of the three-dimensional electronic circuit device which concern on Embodiment 1 of this invention The top view and sectional drawing which expanded and showed the principal part of FIG. A plan view and a sectional view of a part of the sheet-like member constituting the connecting member A plan view and a sectional view for explaining the bonding process of the connecting member to the circuit board. Sectional drawing which shows the other example of a sheet-like member The top view which shows the other example of a sheet-like member Plan view of relevant parts of a three-dimensional electronic circuit device according to Embodiment 2 of the present invention Plan view of relevant parts of a three-dimensional electronic circuit device according to Embodiment 3 of the present invention Sectional drawing of a part of sheet-like member used in Embodiments 2 and 3 Sectional drawing of a part of sheet-like member used for the three-dimensional electronic circuit device according to Embodiment 4 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Three-dimensional electronic circuit apparatus 111, 112 Circuit board 113 Semiconductor chip 114 Electronic component 115 End surface electrode 116 Bare chip 117 Wiring pattern 120a-120c Connection member 121a-121d Sheet-like member 122 Metal wire 123 Anisotropic conductive film 124a-124c Groove

Claims (7)

  A three-dimensional circuit device in which a plurality of circuit boards on which electronic components are mounted are electrically connected to each other at their end faces, arranged in multiple layers so that the main surfaces overlap.
  The end face of each circuit board has a plurality of end face electrodes arranged at a first pitch interval,
  The end surface electrodes of the circuit boards are electrically connected via a connecting member in the multilayer direction,
  The connecting member includes an anisotropic conductive member that connects the surfaces of the end face electrodes, and a sheet-like member that is in contact with the anisotropic conductive member,
  A plurality of conductive wires extending in the multilayer direction intermittently arranged at a second pitch interval narrower than the first pitch interval on the surface of the sheet-like member;
  A three-dimensional electronic circuit device in which the anisotropic conductive member is in contact with at least one of the conductive wires.   The three-dimensional electronic circuit device according to claim 1, wherein two or more of the conductive wires pass through one end face electrode.   The cross-sectional shape of the end face electrode is an arc,
  3. The three-dimensional electronic circuit device according to claim 1, wherein the second pitch interval is less than ½ of the inner circumference of the arc. The three-dimensional electronic circuit device according to any one of claims 1 to 3, wherein the sheet-like member has a plurality of grooves formed on a surface different from a surface on which the conducting wire is disposed.   The three-dimensional electronic circuit device according to claim 4, wherein the groove is formed in parallel with a direction in which the conducting wire extends. The three-dimensional electronic circuit device according to any one of claims 1 to 5, wherein the sheet-like member has a plurality of holes formed on a surface opposite to a surface on which the conducting wire is disposed. Wherein one of said conductors disposed surface of the sheet-like member, between said multiple wire, three-dimensional according to any one of claims 1-6, wherein the conductor and parallel to the groove is formed Electronic circuit device.

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