WO2014125973A1

WO2014125973A1 - Resin multi-layer substrate with built-in component, and resin multi-layer substrate

Info

Publication number: WO2014125973A1
Application number: PCT/JP2014/052664
Authority: WO
Inventors: 喜人大坪; 酒井　範夫
Original assignee: 株式会社村田製作所
Priority date: 2013-02-12
Filing date: 2014-02-05
Publication date: 2014-08-21
Also published as: JP6139653B2; JPWO2014125973A1

Abstract

Provided is a resin multi-layer substrate with built-in component which is capable of improving reliability of a connection between a composite substrate and the resin multi-layer substrate. A resin multi-layer substrate with built-in component (101) is provided with a resin multi-layer substrate (2), and a composite substrate (3). The resin multi-layer substrate (2) is formed by stacking a plurality of resin layers (21), a wire (8) is formed in the interior of the substrate, and a cavity is formed in the main surface (4) thereof. The composite substrate (3) includes components (32), a core substrate (31) mounting the components (32), and connection terminals (9) which electrically connect the wire (8) and the core substrate (31). The wire (8) includes side surface electrodes (29) which are exposed on inner side surfaces of the cavity. The connection terminals (9) are exposed on outer side surfaces (39) of the composite substrate, and are electrically connected to the side surface electrodes (29).

Description

Component built-in resin multilayer substrate and resin multilayer substrate

The present invention relates to a component built-in resin multilayer substrate and a resin multilayer substrate.

Conventionally, a technology has been proposed for mounting electronic components on the main surface of a flexible printed circuit board by providing connection pads on the main surface of the flexible printed circuit board and soldering and fixing the electronic component terminals in contact with the connection pads. (See, for example, Japanese Patent Laid-Open No. 9-18112 (Patent Document 1)).

Japanese Patent Laid-Open No. 9-18112

When an electronic component is mounted on the connection electrode on the main surface of the flexible substrate, stress is directly applied to the electronic component against bending or twisting of the flexible substrate. As a result, there arises a problem that the connection reliability between the electronic component and the flexible substrate is lowered.

Accordingly, an object of the present invention is to provide a component-embedded resin multilayer substrate that can improve the connection reliability between a composite substrate mounted on a flexible resin multilayer substrate and the resin multilayer substrate, and a resin multilayer substrate. And

In order to achieve the above object, the component built-in resin multilayer substrate according to the present invention includes a resin multilayer substrate and a composite substrate. The resin multilayer substrate is formed by laminating a plurality of resin layers. The resin multilayer substrate has a main surface. Wiring is formed inside the resin multilayer substrate, and a cavity is formed on the main surface. The composite substrate is disposed in the cavity. The composite substrate includes a component, a core substrate on which the component is mounted, a sealing resin that seals the component, and a connection terminal that electrically connects the wiring and the core substrate. The cavity has an inner surface. The wiring includes side electrodes exposed on the inner side surface. The composite substrate has an outer surface. The connection terminal is exposed on the outer surface and is electrically connected to the side electrode.

According to the present invention, since the connection terminal exposed on the outer side surface of the composite substrate is electrically connected to the side electrode exposed on the inner side surface of the cavity, the connection reliability between the composite substrate and the resin multilayer substrate is achieved. Can be improved.

It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 1 based on this invention. It is sectional drawing of the state before mounting the composite substrate in the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 1st process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 2nd process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 3rd process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 4th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 5th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 6th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 7th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 8th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 1st process of the manufacturing method of the composite substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 2nd process of the manufacturing method of the composite substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 3rd process of the manufacturing method of the composite substrate in Embodiment 1 based on this invention. FIG. 14 is a cross-sectional view taken along line XIV-XIV shown in FIG. It is explanatory drawing of the 4th process of the manufacturing method of the composite substrate in Embodiment 1 based on this invention. It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 2 based on this invention. It is sectional drawing of the state before mounting the composite substrate in the resin multilayer substrate in Embodiment 2 based on this invention. It is explanatory drawing of the 1st process of the manufacturing method of the resin multilayer substrate in Embodiment 2 based on this invention. It is explanatory drawing of the 2nd process of the manufacturing method of the resin multilayer substrate in Embodiment 2 based on this invention. It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 3 based on this invention. It is sectional drawing of the state before mounting the composite substrate in the resin multilayer substrate in Embodiment 3 based on this invention. It is sectional drawing of the state in the middle of mounting the composite substrate in the resin multilayer substrate in Embodiment 3 based on this invention. It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 4 based on this invention. It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 5 based on this invention. It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 6 based on this invention. It is sectional drawing of the component built-in resin multilayer substrate in Embodiment 7 based on this invention.

(Embodiment 1)
(Constitution)
A component built-in resin multilayer substrate 101 according to the first embodiment of the present invention will be described with reference to FIGS. The component built-in resin multilayer substrate 101 includes a resin multilayer substrate 2 and a composite substrate 3. The resin multilayer substrate 2 has a main surface 4. The component built-in resin multilayer substrate 101 is formed by mounting the composite substrate 3 on the main surface 4 of the resin multilayer substrate 2.

The resin multilayer substrate 2 is formed by laminating and integrating a plurality of resin layers 21. The direction in which the plurality of resin layers 21 are stacked, that is, the vertical direction in the cross-sectional view shown in FIG. 1 is referred to as the thickness direction of the resin multilayer substrate 2. Inside the resin multilayer substrate 2, conductive wiring 8 is formed. The wiring 8 includes a plurality of via conductors 6 and a plurality of conductor patterns 7. The via conductor 6 extends in the thickness direction of the resin layer 21 and is formed so as to penetrate the resin layer 21 in the thickness direction. The conductor pattern 7 extends in a plane direction orthogonal to the thickness direction of the resin layer 21 and is disposed on the main surface of the resin layer 21. Via conductors 6 formed so as to penetrate the resin layer 21 in the thickness direction electrically connect the conductor patterns 7 formed in the different resin layers 21, thereby forming the wiring 8.

2, cavities 22 for mounting the composite substrate 3 are formed on the main surfaces 4 on both sides of the resin multilayer substrate 2. The cavity 22 is formed in a shape in which a part of the main surface 4 of the resin multilayer substrate 2 is recessed. The cavity 22 is open to the main surface 4, has a bottom surface 25 and an inner surface 26, and defines a hollow space therein. The inner side surface 26 is a surface that extends along the thickness direction of the resin multilayer substrate 2 and forms the inner wall of the cavity 22. A part of the via conductor 6 constituting the wiring 8 is exposed on the inner side surface 26 of the cavity 22. The wiring 8 includes a side electrode 29 exposed on the inner side surface 26. The side electrode 29 is formed by the via conductor 6.

The composite substrate 3 includes a core substrate 31. The core substrate 31 has a facing surface 37 facing the resin multilayer substrate 2 and a back surface 38 opposite to the facing surface 37. The core substrate 31 has a flat outer shape, and one of a pair of main surfaces is formed as a facing surface 37 and the other is formed as a back surface 38. A surface conductor (not shown) is provided on the facing surface 37 and the back surface 38 of the core substrate 31, and an internal conductor (not shown) is provided inside the core substrate 31.

A plurality of components 32 are mounted on the facing surface 37 side of the core substrate 31. The second component 34 is mounted on the back surface 38 side of the core substrate 31. The composite substrate 3 includes a plurality of components 32 mounted on the facing surface 37 of the core substrate 31 and a second component 34 mounted on the back surface 38 of the core substrate 31. Each of the plurality of components 32 is electrically connected to a surface conductor provided on the facing surface 37. The second component 34 is bonded to the back surface 38 of the core substrate 31 by a bonding member 35 such as a solder ball, and is electrically connected to the surface conductor provided on the back surface 38.

A sealing resin 33 for sealing the component 32 is provided on the facing surface 37 side of the core substrate 31. A sealing resin 36 that seals the second component 34 is provided on the back surface 38 side of the core substrate 31. The part 32 and the second part 34 are protected from the external environment such as stress or moisture by being covered with the sealing resins 33 and 36, respectively. By providing the sealing resins 33 and 36, the close contact between the core substrate 31, the component 32, and the second component 34 is maintained, and the pickup property when the composite substrate 3 is mounted is improved. The composite substrate 3 is a double-sided mounting type substrate in which components are mounted on both main surfaces of the core substrate 31, and a double-sided sealing type substrate in which both main surfaces of the core substrate 31 are sealed with resin. It is.

The composite substrate 3 is mounted on the main surface 4 of the resin multilayer substrate 2 by being fitted into the cavity 22. In a state where the composite substrate 3 is mounted on the main surface 4 of the resin multilayer substrate 2, the composite substrate 3 is disposed in the cavity 22, and the opposing surface 37 of the core substrate 31 and a plurality of components mounted on the opposing surface 37. The component 32 is built in the resin multilayer substrate 2. On the other hand, the back surface 38 of the core substrate 31 and the second component 34 mounted on the back surface 38 are disposed outside the resin multilayer substrate 2.

The component built-in resin multilayer substrate 101 also includes a connection terminal 9. The connection terminal 9 is made of a conductive material, and is fixed to the facing surface 37 of the core substrate 31. The connection terminal 9 extends in the thickness direction of the core substrate 31. The connection terminal 9 has a pin shape, and a plurality of connection terminals 9 are arranged along the outer periphery of the core substrate 31. A plurality of components 32 and a plurality of pin-shaped connection terminals 9 are arranged on the facing surface 37 side of the core substrate 31. A component 32 is mounted on the facing surface 37 on which the pin-shaped connection terminals 9 are formed.

The composite substrate 3 has an outer surface 39. The outer side surface 39 is a surface of the composite substrate 3 that extends in a direction intersecting the facing surface 37 and the back surface 38 of the core substrate 31, typically in a direction orthogonal thereto. In the state where the composite substrate 3 is mounted on the resin multilayer substrate 2 shown in FIG. 1, the outer side surface 39 extends along the thickness direction of the resin multilayer substrate 2. A part of the outer peripheral surface of the connection terminal 9 is exposed on the outer surface 39. The connection terminal 9 has an exposed surface that is not covered with the sealing resin 33 at a part of its front end surface and outer peripheral surface.

In a state where the composite substrate 3 is mounted on the resin multilayer substrate 2, a part of the outer side surface 39 of the composite substrate 3 faces the inner side surface 26 of the cavity 22, and a part of the outer side surface 39 and the inner side surface 26. Are in surface contact. One end of the connection terminal 9 is fixed to the core substrate 31 and is electrically connected to the surface conductor formed on the facing surface 37. The tip end surface at the other end of the connection terminal 9 is in contact with the conductor pattern 7 constituting a part of the wiring 8. The connection terminal 9 has a length that can reliably reach the tip of the wiring terminal 8 formed inside the resin multilayer substrate 2 in the thickness direction of the core substrate 31. Further, the outer peripheral surface of the connection terminal 9 exposed on the outer side surface 39 is in contact with the side electrode 29 exposed on the inner side surface 26 and is electrically connected to the side electrode 29. Thus, the connection terminal 9 electrically connects the wiring 8 that is an electrode on the resin multilayer substrate 2 side and the core substrate 31 that is an electrode on the composite substrate 3 side.

(Action / Effect)
In the present embodiment, the main surface 4 of the resin multilayer substrate 2 is formed with a hollow cavity 22 in which the main surface 4 is depressed, and the composite substrate 3 is mounted on the resin multilayer substrate 2. The part 32 is accommodated in the cavity 22. The entire composite substrate 3 is not mounted so as to protrude from the main surface 4 of the resin multilayer substrate 2, and a part of the composite substrate 3 including the component 32 is built in the resin multilayer substrate 2. As a result, in the component-embedded resin multilayer substrate 101, the thickness of the composite substrate 3 protruding from the main surface 4 of the resin multilayer substrate 2 can be reduced, so that the dimension in the thickness direction of the component-embedded resin multilayer substrate 101 can be reduced and the height can be reduced. Can be achieved.

Part of the composite substrate 3 is embedded in the cavity 22. When the component built-in resin multilayer substrate 101 is viewed in plan, the composite substrate 3 is surrounded by the resin multilayer substrate 2 in the entire circumferential direction. The component 32 is covered with the sealing resin 33 and the resin multilayer substrate 2 and protected from the external environment. Since the resin multilayer substrate 2 has flexibility and elasticity, the adhesion between the resin multilayer substrate 2 and the composite substrate 3 is improved, and the holding power of the composite substrate 3 is enhanced. In addition, since the impact applied to the component 32 when the component-embedded resin multilayer substrate 101 is dropped is reduced, the impact resistance of the component-embedded resin multilayer substrate 101 can be improved.

The component 32 is an electronic component such as a multilayer ceramic capacitor, an integrated circuit, or a semiconductor element, and generates heat when a current flows. The component 32 according to the present embodiment is mounted on the core substrate 31, and one of the outer peripheral surfaces of the component 32 faces the core substrate 31. As a result, the heat generated in the component 32 is transmitted from the component 32 to the core substrate 31 and is transmitted to the outside via the core substrate 31. Thereby, heat dissipation from the component 32 is performed efficiently. Since the heat dissipation of the component 32 can be improved, the occurrence of problems due to overheating of the component 32 can be suppressed.

In this embodiment, pin-shaped connection terminals 9 are provided on the composite substrate 3, and the connection terminals 9 are exposed on the outer surface 39 of the composite substrate 3. A cavity 22 is formed on the main surface 4 of the resin multilayer substrate 2, and the wiring 8 is exposed on the inner side surface 26 of the cavity 22 to form side electrodes 29. The composite substrate 3 is mounted on the resin multilayer substrate 2 by embedding a part of the composite substrate 3 in the cavity 22 formed on the main surface 4 of the resin multilayer substrate 2. In a state where the composite substrate 3 is mounted on the main surface 4 of the resin multilayer substrate 2, the connection terminal 9 is electrically connected to the side electrode 29. By adopting this configuration, if the composite substrate 3 is fitted into the cavity 22, the component 32 can be placed in a predetermined position, so that the displacement of the composite substrate 3 with respect to the resin multilayer substrate 2 can be prevented. It can be arranged with high accuracy.

By using the pin-shaped connection terminal 9, the electrical resistance can be reduced as compared with a configuration in which only the via conductor 6 is used for electrical connection between the wiring 8 and the core substrate 31. By extending the metal pins in the thickness direction of the resin multilayer substrate 2, the bending stress acting on the core substrate 31 when the bending stress acts on the resin multilayer substrate 2 can be reduced. Therefore, the composite substrate 3 and the resin multilayer substrate 2 can be reduced. Connection reliability can be improved.

In addition to the tip end surface of the pin-shaped connection terminal 9 contacting the conductor pattern 7, the outer peripheral surface of the connection terminal 9 exposed on the outer surface 39 of the composite substrate 3 is exposed on the inner surface 26 of the cavity 22. The core substrate 31 of the composite substrate 3 and the wiring 8 are electrically connected by contacting the side electrode 29 that is present. At this time, the composite substrate 3 having the solder applied to the side electrode 29 is inserted into the cavity 22, the side electrode 29 is brought into contact with the wiring 8, the solder is melted in this state, and then cooled, so that the side electrode 29 The metal is joined to 8 via solder. If the side electrode 29 and the wiring 8 are fixed in this way, the composite substrate 3 can be prevented from coming out of the cavity 22. On the other hand, the composite substrate 3 can be attached to and detached from the resin multilayer substrate 2 by electrically connecting the side electrode 29 and the wiring 8 by physical contact.

Compared with the front end face of the connection terminal 9, the side electrode 29 extending in the thickness direction of the resin multilayer substrate 2 is less susceptible to the stress caused by bending or twisting of the resin multilayer substrate 2. Therefore, the bonding strength between the composite substrate 3 and the resin multilayer substrate 2 can be improved by bonding using the side surface in addition to the front end surface of the connection terminal 9. Connection reliability can be improved. In a state where the composite substrate 3 is mounted on the resin multilayer substrate 2, the electrodes that electrically connect the composite substrate 3 and the resin multilayer substrate 2 are not exposed to the outside. As a result, since the electrode can be prevented from being directly subjected to electrostatic discharge, the electrostatic resistance of the component-embedded resin multilayer substrate 101 can be improved.

In the present embodiment, the side electrode 29 is formed by the via conductor 6 extending in the thickness direction of the resin layer 21 constituting the resin multilayer substrate 2. By adopting this configuration, the side electrode 29 can be easily formed without the need for complicated work steps in forming the side electrode 29.

In the present embodiment, the composite substrate 3 includes a component 32 mounted on the facing surface 37 side of the core substrate 31 and a second component 34 mounted on the back surface 38 side of the core substrate 31. By adopting this configuration, the composite substrate 3 having components mounted on both sides of the core substrate 31 is mounted on the resin multilayer substrate 2, so that the mounting density of components on the resin multilayer substrate 2 can be further increased.

(Production method)
The method for manufacturing the component-embedded resin multilayer substrate 101 in the present embodiment includes a step of preparing a perforated resin sheet in which a plurality of through holes penetrating in the thickness direction are formed, a resin sheet, and another resin sheet are laminated. The composite substrate 3 including the step of forming the resin multilayer substrate 2 having the cavity 22 formed on the main surface 4 by pressure bonding and the core substrate 31 and the plurality of components 32 mounted on the core substrate 31 is inserted into the through hole. And mounting on the resin multilayer substrate 2. With reference to FIG. 3 to FIG. 15, the method for manufacturing the component-embedded resin multilayer substrate 101 in the present embodiment will be described in more detail.

First, a resin sheet 12 with a conductive foil as shown in FIG. 3 is prepared. The resin sheet with conductor foil 12 is a sheet having a structure in which the conductor foil 17 is attached to one surface of the resin layer 21. The resin layer 21 is made of, for example, a thermoplastic resin. The thermoplastic resin may be, for example, LCP (liquid crystal polymer), PEEK (polyether ether ketone), PEI (polyether imide), PPS (poniphenylene sulfide), thermoplastic PI (polyimide), and the like. The material of the conductor foil 17 may be Cu, Ag, Al, SUS, Ni, Au, or may be an alloy of two or more different metals selected from these metals. The thickness of the conductor foil 17 may be any thickness that allows circuit formation of about 2 μm to 50 μm. For example, the conductor foil 17 may be a foil having a thickness of 18 μm. The surface of the conductive foil 17 is formed so that the surface roughness Rz is 3 μm, for example.

After preparing a plurality of strip-shaped resin sheets 12 with conductor foil, the following conductor pattern forming operation may proceed. However, as another method, Next, prepare a plurality of resin sheets with strip-shaped areas that should be cut out individually, proceed with the formation work of the following conductor patterns etc. in large size, and then cut into strips Also good. Here, the description will be continued assuming that the strip-shaped resin sheet 12 with conductive foil has already been cut out.

Next, as shown in FIG. 4, the resin layer 21 is penetrated by irradiating the surface of the resin layer 21 side opposite to the surface to which the conductor foil 17 of the resin sheet 12 with conductor foil adheres with a carbon dioxide laser beam. The via hole 11 is formed as described above. The via hole 11 penetrates the resin layer 21 but does not penetrate the conductor foil 17. Thereafter, the smear in the via hole 11 is removed by chemical treatment such as permanganic acid as necessary. In order to form the via hole 11, a laser beam of a different type from the carbon dioxide laser beam may be used. However, it is preferable to use laser light that penetrates the resin layer 21 but does not penetrate the conductor foil 17. Further, in order to form the via hole 11, a method other than laser beam irradiation, such as punching, may be employed.

Next, as shown in FIG. 5, a resist pattern 13 corresponding to a desired circuit pattern is printed on the surface of the conductor foil 17 of the resin sheet 12 with a conductor foil by a method such as screen printing. Next, etching is performed using the resist pattern 13 as a mask, and as shown in FIG. 6, the portion of the conductor foil 17 that is not covered with the resist pattern 13 is removed. A portion of the conductor foil 17 remaining after the etching becomes the conductor pattern 7. Thereafter, the resist pattern is removed using a cleaning solution or the like.

In this way, a plurality of via holes 11 penetrating through the resin layer 21 in the thickness direction are formed, and a desired conductor pattern 7 is formed on one surface of the resin layer 21, so that the perforated resin shown in FIG. A sheet is obtained. Note that the order of forming the via hole 11 and the conductor pattern 7 is not limited to the order described above, and may be the order in which the via hole 11 is formed after the conductor pattern 7 is formed.

Next, a conductive paste is filled into the via hole 11 formed in the resin layer 21 by screen printing or the like. Screen printing is performed from the surface on the side where the conductor pattern 7 is not disposed, that is, the lower surface in FIG. Actually, when performing screen printing, the orientation of the perforated resin sheet may be appropriately changed. The conductive paste to be filled may contain an appropriate amount of metal powder that forms an alloy layer with the metal that is the material of the conductor pattern 7 at the temperature when the laminated resin layer 21 is thermocompression bonded later. preferable. This conductive paste preferably contains at least one of Ag, Cu, and Ni and at least one of Sn, Bi, and Zn.

By filling the conductive paste in this manner, the configuration shown in FIG. 8 is obtained in which the via conductor 6 is inserted into the through hole of the perforated resin sheet and the via conductor 6 penetrating the resin layer 21 in the thickness direction is formed.

Up to this point, the processing in one resin layer 21 has been described as an example. However, in the other resin layers 21 as well, the same processing is performed to appropriately form a conductor pattern 7 in a desired region, and vias are provided as necessary. A conductor 6 is formed.

Next, as shown in FIG. 9, through holes 14 are formed in the resin layer 21 by punching. When the through hole 14 is viewed in plan, the through hole 14 has an area corresponding to the projected area of the composite substrate 3. At the time of punching for forming the through hole 14, the punching die and the resin layer 21 are relatively moved in a direction along the thickness direction of the resin layer 21. The mold moves relative to the resin layer 21 so that the periphery of the mold passes through the via conductor 6. As a result, the resin layer 21 is punched out so that the via conductor 6 is partially cut, and the through hole 14 is formed. As a result, the via conductor 6 is exposed on the inner surface of the through hole 14.

Next, a plurality of resin layers 21 including the perforated resin sheet shown in FIG. 9 and another resin sheet are laminated to form a laminate. The plurality of resin layers forming the laminated body include a resin layer in which the through holes 14 are formed and a resin layer in which the through holes 14 are not formed. Subsequently, pressure and heat are applied to the laminate of the plurality of resin layers 21. In this way, the plurality of resin layers 21 included in the laminate are thermocompression bonded together, and as a result, the resin multilayer substrate 2 shown in FIG. 10 is formed. You may heat and pressurize by putting a release material on the upper and lower surfaces of a laminated body, and also inserting | pinching with the press board from the upper and lower sides. By using the release material, the work of taking out the resin multilayer substrate 2 obtained after thermocompression bonding from between the press plates can be performed smoothly.

In the resin multilayer substrate 2 shown in FIG. 10, two resin layers 21 having through holes 14 are stacked on a resin layer 21 having no through holes 14 formed thereon. A cavity 22 is formed by combining two through holes 14. By combining the through holes 14 formed in the resin layer 21 by an arbitrary number of layers, the resin layer 21 has an arbitrary depth (that is, a distance between the main surface 4 and the bottom surface 25 in the thickness direction of the resin multilayer substrate 2). A cavity 22 is formed.

In the resin multilayer substrate 2, the perforated resin sheet shown in FIG. 9 is on the side away from the main surface 4 of the resin multilayer substrate 2, that is, on the bottom surface 25 of the cavity 22, of the two resin layers 21 forming the cavity 22. Laminated on the near side. As a result, a side electrode 29 where the wiring 8 is exposed to the inner side surface 26 of the cavity 22 is formed on a part of the inner side surface 26 of the cavity 22 on the side close to the bottom surface 25.

Next, the composite substrate 3 is prepared. The composite substrate 3 is manufactured by the following steps. First, as shown in FIG. 11, a base substrate 131 is prepared. The base substrate 131 is a collective substrate that can cut out a plurality of substrates to be the core substrate 31 by being cut along a cutting line CL indicated by a two-dot chain line in FIG. The base substrate 131 has a front surface 137 and a back surface 138. The surface 137 is one main surface of the base substrate 131 corresponding to the facing surface 37 of the core substrate 31. The back surface 138 is the other main surface of the base substrate 131 corresponding to the back surface 38 of the core substrate 31. The base substrate 131 is formed of a printed circuit board (PCB), a low-temperature co-fired ceramic (LTCC), an alumina substrate, a glass substrate, a composite material substrate, a single layer substrate, a multilayer substrate, or the like using a resin or a polymer material. The base substrate 131 may be formed by selecting an optimal material as appropriate according to the purpose of use of the composite substrate 3.

The base substrate 131 is a multilayer ceramic substrate in which a plurality of ceramic green sheets are laminated and fired. The ceramic green sheet is a sheet obtained by forming a slurry in which a mixed powder such as alumina and glass is mixed with an organic binder and a solvent. Via holes are formed at predetermined positions of the ceramic green sheet by laser processing, etc., and the via holes formed are filled with a conductor paste containing Ag, Cu, etc., and via conductors for interlayer connection are formed. The electrode pattern is formed. Thereafter, the ceramic green sheets are laminated and pressed to form a ceramic laminate, and the ceramic laminate is fired at a low temperature of about 1000 ° C. at a so-called low temperature to form the base substrate 131. The As described above, the base substrate 131 is provided with various electrode patterns such as mounting electrodes and external connection electrodes on which the internal wiring, the terminal assembly, and the component 32 are mounted.

When the base substrate 131 is formed using the LTCC substrate, first, a ceramic slurry is coated on a PET film and then dried to form a ceramic green sheet having a thickness of 10 to 200 μm. A via hole having a diameter of about 0.1 mm is formed on the prepared ceramic green sheet from the PET film side by a mold, a laser, or the like. Next, an electrode paste kneaded with metal powder containing silver or copper as a main component, resin, and organic solvent is filled in the via hole and dried. Then, an equivalent electrode paste is screen-printed in a desired pattern on the ceramic green sheet and dried. In this state, a plurality of ceramic green sheets are stacked and pressure-bonded at a pressure of 100-1500 kg / cm ² and a temperature of 40-100 ° C. Thereafter, when the electrode paste is mainly composed of silver, the electrode paste is fired at about 850 ° C. in air, and when copper is the main component, it is fired at about 950 ° C. in a nitrogen atmosphere. A base substrate 131 is formed by depositing Au or the like by wet plating or the like.

Next, solder 132 is printed on a desired surface electrode among the surface electrodes of the base substrate 131. In the case of the present embodiment, as shown in FIG. 11, the solder 132 is printed at a position where a plurality of components 32 are to be mounted, and the solder 132 is printed so as to straddle both sides of the cutting line CL.

Next, as shown in FIG. 12, a plurality of components 32 that are electronic components such as various chip components, integrated circuits, or semiconductor elements are printed on the solder 132 on the surface 137 that is one main surface of the base substrate 131. Mount on the surface electrode. Similarly, the second component 34, which is an electronic component, is mounted at a predetermined position on the back surface 138, which is the other main surface of the base substrate 131, using the bonding member 35.

A plurality of terminal connection substrates 109 are further mounted on the surface 137. The terminal connection substrate 109 is mounted on the surface electrode of the base substrate 131 at a position where it does not come into contact with the plurality of components 32 mounted on the surface 137. For example, as shown in FIG. 12, the terminal connection substrate 109 may be arranged on two opposite sides of the outer periphery of the base substrate 131, or the terminal connection substrate 109 may be arranged on the four sides of the outer periphery of the base substrate 131. Also good.

The terminal connection substrate 109 is formed of a copper foil having a predetermined thickness. The thickness of the terminal connection substrate 109 is determined so that the height at which the terminal connection substrate 109 protrudes from the surface 137 is larger than the height at which the component 32 protrudes from the surface 137. The copper foil may be made of pure copper, or may be made of a copper alloy such as an alloy in which iron is mixed with copper at a ratio of 0.1% to 20%, phosphor bronze, brass or the like. Since copper alloy has higher workability than pure copper, it has the advantage that burrs and elongation are less likely to occur during subsequent cutting with a dicer and polishing of the upper surface. Note that the terminal connection substrate 109 may be formed of another metal conductor such as Au, Ag, or Al.

The component 32, the second component 34, and the terminal connection substrate 109 may be mounted by a general surface mounting technique such as ultrasonic vibration bonding in addition to solder reflow.

Subsequently, the base substrate 131 is cut along the cutting line CL using a dicer. By this division, the terminal connection substrate 109 is also divided at the same time. In this way, the base substrate 131 is singulated and the core substrate 31 is formed. The core substrate 31 has a facing surface 37 and a back surface 38, a plurality of components 32 and connection terminals 9 are mounted on the facing surface 37, and a second component 34 is mounted on the back surface 38. Since the terminal connection substrate 109 is disposed so as to straddle the cutting line CL, a structure in which the connection terminal 9 is exposed to the side surface is obtained as shown in FIGS.

Subsequently, a resin sheet is laminated on both the facing surface 37 and the back surface 38 of the core substrate 31. Thereby, a sealing resin 33 for sealing the component 32 mounted on the opposing surface 37 and a sealing resin 36 for sealing the second component 34 mounted on the back surface 38 are formed. The facing surface 37 of the core substrate 31 is filled with the sealing resin 33, and the component 32 mounted on the facing surface 37 of the core substrate 31 is sealed with the sealing resin 33. In addition, the back surface 38 of the core substrate 31 is filled with the sealing resin 36, and the second component 34 mounted on the back surface 38 of the core substrate 31 is sealed with the sealing resin 36.

The resin sheet may be formed of a composite resin formed by mixing an inorganic filler such as aluminum oxide, silica (silicon dioxide), or titanium dioxide with a thermosetting resin such as an epoxy resin, a phenol resin, or a cyanate resin. it can. For example, when the sealing resins 33 and 36 are formed using a resin sheet obtained by molding a composite resin on a PET film and semi-cured, a spacer (mold) having a desired thickness is arranged around The core substrate 31 is covered with a resin sheet, and the resin sheet is heated and pressed so that the thickness of the resin becomes the thickness of the spacer, and then the core substrate 31 is heated in an oven to cure the resin. Thereby, the sealing resins 33 and 36 having a desired thickness can be formed.

The sealing resins 33 and 36 may be formed using a general molding technique for forming a resin layer, such as a potting technique using a liquid resin, a transfer molding technique, or a compression molding technique. The resin sheets may be laminated and cured together on both the opposing surface 37 and the back surface 38, but the resin sheets may be laminated and cured separately on the opposing surface 37 and the back surface 38, respectively.

The surface of the sealing resin 33 on the side away from the core substrate 31, that is, the upper surface of the sealing resin 33 shown in FIG. 15 may be polished using a roller blade or the like. Thereby, even when the heights of the plurality of connection terminals 9 vary, the shape of the plurality of connection terminals 9 exposed from the top surface of the sealing resin 33 as a result of polishing the cured sealing resin 33. Can be substantially matched.

The composite substrates 3 shown in FIG. 15 may be individually manufactured according to the above-described steps. However, after forming an aggregate of a plurality of composite substrates 3, the composite substrates 3 are separated into individual composite substrates 3. May be manufactured.

The composite substrate 3 manufactured in this way is mounted on the main surface 4 of the resin multilayer substrate 2. A cavity 22 is formed on the main surface 4 of the resin multilayer substrate 2, and a side electrode 29 is exposed on the inner side surface 26 of the cavity 22. On the other hand, the connection terminals 9 are exposed on the outer surface 39 of the composite substrate 3. Therefore, by inserting the composite substrate 3 into the cavity 22, the side electrode 29 and the connection terminal 9 are in surface contact, and the wiring 8 and the core substrate 31 are electrically connected. In this state, the composite substrate 3 is bonded to the resin multilayer substrate 2 using solder, whereby the mounting of the composite substrate 3 on the resin multilayer substrate 2 is completed, and the component built-in resin multilayer substrate 101 shown in FIG. 1 is obtained.

By carrying out the manufacturing method in this way, it is possible to easily obtain the component built-in resin multilayer substrate 101 in which the composite substrate 3 is partially accommodated in the cavity 22 and the thickness is reduced. Due to the flexibility of the resin multilayer substrate 2, the adhesion between the resin multilayer substrate 2 and the composite substrate 3 can be improved, and the holding power of the composite substrate 3 can be increased. Since the composite substrate 3 and the resin multilayer substrate 2 are electrically connected when the side surface of the connection terminal 9 is in contact with the side electrode 29, the connection strength between the composite substrate 3 and the resin multilayer substrate 2 is improved. The reliability can be improved and the static electricity resistance of the component built-in resin multilayer substrate 101 can be improved.

(Embodiment 2)
A component built-in resin multilayer substrate 101 according to the second embodiment of the present invention will be described with reference to FIGS. In the component built-in resin multilayer substrate 101 according to the second embodiment, the entire core substrate 31 is accommodated in a cavity 22 formed on the main surface 4 of the resin multilayer substrate 2. In the component-embedded resin multilayer substrate 101 according to the second embodiment, the number of portions of the composite substrate 3 that are embedded in the resin multilayer substrate 2 is increased as compared with the first embodiment. With this configuration, the holding power of the composite substrate 3 by the resin multilayer substrate 2 can be further improved.

The connection terminals 9 exposed on the outer surface 39 of the composite substrate 3 are pierced by via conductors 6 formed inside the resin multilayer substrate 2. The via conductor 6 is made of a conductive paste mainly composed of Ag, a conductive paste mainly composed of Sn—Ag alloy, a conductive paste mainly composed of bismuth, a tin solder material, or a conductive material such as copper. Is formed. Since the formation material of the via conductor 6 becomes soft when heated, the formation material of the connection terminal 9 becomes relatively hard compared to the formation material of the via conductor 6. Therefore, from the state where the composite substrate 3 is inserted into the cavity 22 and the tip end surface of the connection terminal 9 is in contact with the via conductor 6 while being heated to about the reflow temperature, the composite substrate 3 is further directed into the resin multilayer substrate 2. The via conductor 6 is easily deformed by pushing it forward. Thus, the structure shown in FIG. 16 in which the connection terminal 9 is pierced into the via conductor 6 is obtained. In addition to the tip end surface of the connection terminal 9 being in contact with the wiring 8, the outer peripheral surface of the connection terminal 9 is in contact with the side electrode 29 formed by the deformed via conductor 6. Thereby, the electrical connection between the wiring 8 and the core substrate 31 via the connection terminal 9 can be reliably formed.

Referring to FIGS. 18 and 19, the production of resin multilayer substrate 2 in the second embodiment based on the present invention will be described. FIG. 18 illustrates a state in which the resin layer 21 in which the via conductors 6 are formed through the same process as in the first embodiment is viewed in a plan view. A two-dot chain line shown in FIG. 18 indicates a cutting line CL where a part of the resin layer 21 is cut by the laser processing of the resin layer 21.

Since the forming material of the resin layer 21 is easier to melt than the metal material forming the via conductor 6, when the resin layer 21 is laser processed along the cutting line CL, the via conductor is formed in the cavity 22 formed by melting the resin layer 21. The structure shown in FIG. 19 in which 6 remains is obtained. Thereby, a configuration in which the side electrode 29 is exposed on the inner side surface 26 of the cavity 22 is obtained. The side electrode 29 is disposed at a position corresponding to the connection terminal 9 provided on the composite substrate 3 in plan view. Therefore, as described above, the connection terminal 9 can be reliably connected to the wiring 8 by fitting the composite substrate 3 into the cavity 22. Laser processing of the resin layer 21 along the cutting line CL may be performed after laminating only the plurality of resin layers 21 in which through holes for forming the cavity 22 are to be formed.

(Embodiment 3)
A component built-in resin multilayer substrate 101 according to the third embodiment of the present invention will be described with reference to FIGS. In the component-embedded resin multilayer substrate 101 of the third embodiment, the main surface 4 of the resin multilayer substrate 2 has a first main surface 4a and a second main surface 4b opposite to the first main surface 4a. Yes. A conductor pattern 7 extending in the surface direction of the resin layer 21 is formed on the main surface of one of the resin layers 21 constituting the resin multilayer substrate 2. A part of the conductor pattern 7 protrudes into the cavity 22. The conductor pattern 7 has an end 7 a that protrudes into the cavity 22. The side electrode 29 is formed of a conductor pattern 7 whose end 7a is bent away from the first main surface 4a and closer to the second main surface 4b. The side electrode 29 is exposed from the inner side surface 26 of the cavity 22 and disposed inside the cavity 22.

The cavity 22 of the third embodiment has an area that is slightly larger than the projected area of the composite substrate 3 in plan view. In a state where the composite substrate 3 shown in FIG. 21 is not mounted on the resin multilayer substrate 2, the conductor pattern 7 extends in the surface direction. The end 7 a of the conductor pattern 7 protrudes toward the inner side of the cavity 22 with respect to the inner side surface 26 of the cavity 22. FIG. 21 shows a configuration in which the end portions 7a of the pair of conductor patterns 7 protrude into the cavity 22 on both the left and right sides in the figure, and the pair of end portions 7a are respectively seen in plan view in the composite substrate 3. It overlaps with the projection.

Since the conductor pattern 7 is formed of conductor foil as described in the first embodiment, it can be easily elastically deformed. The composite substrate 3 and the resin multilayer substrate 2 are moved relative to each other so that the composite substrate 3 is disposed inside the cavity 22 from the state where the composite substrate 3 shown in FIG. Contacts the end 7 a of the conductor pattern 7. Further, by pushing the composite substrate 3 into the cavity 22, the conductor pattern 7 in contact with the composite substrate 3 is such that the end portion 7a is away from the first main surface 4a and approaches the second main surface 4b as shown in FIG. Bend to. Then, in the state shown in FIG. 20 where the mounting of the composite substrate 3 on the resin multilayer substrate 2 is completed, the end 7a of the conductor pattern 7 is electrically connected to the surface exposed to the outer surface 39 of the connection terminal 9. The side electrode 29 is formed.

By adopting this configuration, since the resin multilayer substrate 2 and the composite substrate 3 are bonded using not only the front end surface but also the side surface of the connection terminal 9, the bonding strength between the composite substrate 3 and the resin multilayer substrate 2 is increased. Can be improved. When the composite substrate 3 is extracted from the cavity 22, the conductor pattern 7 forming the side electrode 29 is elastically deformed again and returns to the shape extending in the surface direction shown in FIG. Therefore, the component built-in resin multilayer substrate 101 in which the composite substrate 3 can be freely attached to and detached from the resin multilayer substrate 2 can be provided.

(Embodiment 4)
With reference to FIG. 23, a component built-in resin multilayer substrate 101 according to the fourth embodiment of the present invention will be described. In the third embodiment, the conductor pattern 7 forming the side electrode 29 is disposed inside the resin multilayer substrate 2. However, as shown in FIG. 23, the conductor pattern 7 of the fourth embodiment is the resin multilayer substrate 2. Is arranged on the first main surface 4a. By adopting this configuration, it is possible to provide a component-embedded resin multilayer substrate 101 that can freely attach and detach the composite substrate 3 to and from the resin multilayer substrate 2 as in the third embodiment.

(Embodiment 5)
With reference to FIG. 24, a component built-in resin multilayer substrate 101 according to the fifth embodiment of the present invention will be described. As shown in FIG. 24, in the component-embedded resin multilayer substrate 101 of the fifth embodiment, the end portion 7a of the conductor pattern 7 and the resin layer 21 on the second main surface 4b side with respect to the conductor pattern 7 are the first main surface. It is bent integrally on the side away from 4a and approaching the second main surface 4b. The bent conductor pattern 7 forms a side electrode 29. By adopting this configuration, it is possible to provide a component-embedded resin multilayer substrate 101 that can freely attach and detach the composite substrate 3 to and from the resin multilayer substrate 2 as in the third embodiment. Since the end portion 7a of the conductor pattern 7 protruding into the cavity 2 and the resin layer 21 are bent together to form the side electrode 29, the strength of the side electrode 29 can be improved.

(Embodiment 6)
With reference to FIG. 25, a component built-in resin multilayer substrate 101 according to the sixth embodiment of the present invention will be described. In the sixth embodiment, the main surface 4 of the resin multilayer substrate 2 has a first main surface 4a and a second main surface 4b opposite to the first main surface 4a. The composite substrate 3 is mounted on both the first main surface 4a and the second main surface 4b. In the composite substrate 3 mounted on both sides of the main surface 4, each of the connection terminals 9 penetrates the via conductor 6. Thereby, since the outer peripheral surface of the connection terminal 9 is in surface contact with the side electrode 29, the electrical connection between the wiring 8 and the core substrate 31 is reliably formed. When viewing the component built-in resin multilayer substrate 101 in a plan view, the composite substrate 3 is mounted on the upper first main surface 4a in FIG. 25, and is mounted on the lower second main surface 4b in FIG. The composite substrate 3 is disposed so as to overlap each other.

By adopting this configuration, the components 32 are mounted on both main surfaces 4 of the resin multilayer substrate 2, so that the mounting density of the components 32 on the resin multilayer substrate 2 can be increased. Therefore, the size of the component built-in resin multilayer substrate 101 can be reduced. In addition, since a structure in which the pair of composite substrates 3 sandwich the resin multilayer substrate 2 is formed, when a bending stress acts on the resin multilayer substrate 2 having flexibility, the composite substrate among the resin multilayer substrates 2 The portion sandwiched between 3 is more difficult to bend. Therefore, since the bending stress acting on the composite substrate 3 can be further reduced, the connection stability between the composite substrate 3 and the resin multilayer substrate 2 can be further improved.

(Embodiment 7)
With reference to FIG. 26, a component built-in resin multilayer substrate 101 according to the seventh embodiment of the present invention will be described. In the seventh embodiment, the composite substrate 3 that is detachable from the resin multilayer substrate 2 described in the third and fourth embodiments has both the first main surface 4a and the second main surface 4b as in the sixth embodiment. Has been implemented. Thereby, since the mounting density of the components 32 on the resin multilayer substrate 2 can be increased, the size of the component-embedded resin multilayer substrate 101 can be reduced.

In the component-embedded resin multilayer substrate 101 of the seventh embodiment, as in the sixth embodiment, when the component-embedded resin multilayer substrate 101 is viewed in plan, the composite substrate 3 mounted on the first main surface 4a and the second main substrate 4a. The composite substrate 3 mounted on the surface 4b is disposed so as to overlap each other. From the viewpoint of suppressing deformation of the resin multilayer substrate 2 sandwiched between the composite substrates 3, the arrangement of the sixth embodiment in which the pair of composite substrates 3 almost completely overlap each other in the thickness direction of the resin multilayer substrate 2 is most preferable. However, even if the composite substrate 3 on both sides of the resin multilayer substrate 2 partially overlaps in the thickness direction of the resin multilayer substrate 2, the deformation amount of the resin multilayer substrate 2 is reduced and the composite substrate 3 is reduced. An effect of reducing the acting stress can be obtained similarly.

It should be noted that the above-described embodiment disclosed herein is illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

2 resin multilayer substrate, 3 composite substrate, 4 main surface, 4a first main surface, 4b second main surface, 6 via conductor, 7 conductor pattern, 7a end, 8 wiring, 9 connection terminal, 21 resin layer, 22 cavity , 25 bottom surface, 26 inner surface, 29 side electrode, 31 core substrate, 32 components, 33, 36 sealing resin, 34 second component, 35 bonding member, 37 facing surface, 38 back surface, 39 outer surface, 101 component built-in Resin multilayer substrate.

Claims

A plurality of resin layers are formed by laminating, having a main surface, wiring is formed inside, a resin multilayer substrate having a cavity formed in the main surface;
A composite substrate disposed in the cavity,
The composite substrate includes a component, a core substrate on which the component is mounted, a sealing resin that seals the component, and a connection terminal that electrically connects the wiring and the core substrate.
The cavity has an inner surface;
The wiring includes a side electrode exposed on the inner surface,
The composite substrate has an outer surface;
The connection terminal is exposed to the outer surface and is electrically connected to the side electrode.
The wiring includes a via conductor extending in the thickness direction of the resin layer,
The component built-in resin multilayer board according to claim 1, wherein the side electrode is formed of the via conductor.
The main surface has a first main surface and a second main surface opposite to the first main surface;
The wiring includes a conductor pattern extending in a surface direction of the resin layer, and the conductor pattern has an end protruding into the cavity,
2. The component-embedded resin multilayer substrate according to claim 1, wherein the side electrode is formed by the conductive pattern having the end bent from the first main surface and the second main surface.
The main surface has a first main surface and a second main surface opposite to the first main surface;
4. The component built-in resin multilayer substrate according to claim 1, wherein the composite substrate is mounted on both the first main surface and the second main surface. 5.
A resin multi-layer substrate in which a plurality of resin layers are laminated, wiring is formed inside, and a cavity is formed on the main surface,
The cavity has an inner surface;
The said wiring is a resin multilayer substrate containing the side electrode exposed to the said inner surface.