JP2008078573A - Built-in multi-layer printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-layer printed wiring board having built-in parts which prevents warpage of substrate, has high wiring density, and can provide reduction in thickness. <P>SOLUTION: The multi-layer printed wiring board, having built-in part includes an electronic component embedded in an insulating layer which is provided in between a first insulating substrate and a second insulating substrate, wherein the electronic component is mounted on a component-mounting pad which is formed on either one of the first insulating substrate or the second insulating substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multilayer printed wiring board, and more particularly to a component built-in type multilayer printed wiring board in which an electronic component is embedded in an inner layer.

  In recent years, with the demand for miniaturization and higher density of multilayer printed wiring boards, there has been an increasing demand for printed wiring boards with built-in components that can be obtained by incorporating electronic components that were conventionally surface-mounted into printed wiring boards. Yes.

  Therefore, as shown in FIG. 11, an electronic component mounting board 25 laminated on a single-sided copper foil substrate 23 provided with an opening of the same size as the electronic component in advance is mounted on the board on which the electronic component 24 is mounted. Polishing until the insulating material of the single-sided copper foil substrate 23 is exposed together with the copper foil, and placing and laminating the polished substrates one above the other through the insulating layer 22 around the other inner wiring substrate 21 Thus, there has been proposed an electronic component built-in type multilayer printed wiring board P26 having a configuration in which the mounting area can be increased three-dimensionally in the stacking direction and high-density mounting is possible (see, for example, Patent Document 1).

  However, in addition to arranging the two substrates containing the electronic components so that the electronic components face each other, the core substrate serving as the central layer of the substrate, the core substrate, and the electronic components are incorporated. Since a resin layer for joining the substrates is necessary, there is a problem that the thickness of the entire substrate increases.

  Therefore, as shown in FIG. 12, the inner via 32 is previously connected between a pair of substrates including a circuit-formed wiring pattern and a mounted electronic component 34 with a conductive resin between the pair of substrates. A component-embedded printed wiring board P27 is proposed that has a structure in which the insulating layer 31 formed with the structure is arranged and laminated (see, for example, Patent Document 2).

  However, in the four-layer IVH structure, since the mounting surfaces of the electronic components are combined, the upper and lower electronic components must be spaced apart by a certain distance or more, and the total thickness of the substrate is less than twice that of the substrate on which the electronic components are mounted. There was a problem that I could not.

  Therefore, as shown in FIG. 13, an electronic component 44 is mounted on the uppermost layer of an inner layer substrate having a plurality of wiring layers, and a connection land, a wiring layer, and an inner layer substrate 45 whose surface has been roughened are produced. A thermosetting resin sheet having an opening on one surface and a copper foil, and an insulating layer 41 and a copper foil 42 having a predetermined thickness are laminated on the other surface of the inner substrate, respectively, and heated and pressed to provide an electronic component built-in core. A multilayer copper clad laminate is manufactured, blind via holes 43 and wiring layers are formed, and further, an insulating resin layer, via holes, and wiring layers are formed by a build-up method, thereby reducing the mounting area and the thickness of the component built-in layer There is proposed a multilayer printed wiring board P28 with a built-in electronic component that can reduce the thickness (for example, see Patent Document 3).

However, although the upper and lower buildup base materials are stacked around the core substrate, the thickness of the buildup base material increases only on the side where the chip components are mounted. There was a problem that it was easy.
JP 2001-119148 A JP 2004-274035 A JP 2004-311736 A

  The present invention has been made in view of the above problems and actual circumstances, and an object of the present invention is to provide a component-embedded multilayer printed wiring board that prevents warping of the substrate, has a high wiring density, and can be thinned.

  That is, the present invention according to claim 1 is a printed wiring board in which an electronic component is embedded in an insulating layer provided between the first and second insulating substrates, and the electronic component is the first and second The above problems are solved by a component built-in type multilayer printed wiring board which is mounted on a component mounting pad formed on any one of the second insulating substrates.

  Thereby, even if an electronic component is built in the inner layer, the substrate is thinned, and a vertical symmetrical structure in which an insulating substrate is provided above and below the electronic component is formed, and warping of the substrate is suppressed.

  According to a second aspect of the present invention, the above-mentioned problems are solved by a component-embedded multilayer printed wiring board in which the first and second insulating substrates are made of the same material.

  Thereby, the vertical symmetry of the substrate structure is increased, and the warpage of the substrate is further suppressed.

  According to a third aspect of the present invention, the above-described problems are solved by a component-embedded multilayer printed wiring board in which the thicknesses of the first and second insulating substrates are substantially the same.

  Thereby, the vertical symmetry of the substrate structure is increased, and the warpage of the substrate is further suppressed.

  According to a fourth aspect of the present invention, there is provided a component built-in type multilayer printed wiring board, wherein wiring layers are provided on the front and back surfaces of the first and second insulating substrates. is there.

  As a result, the vertical symmetry of the substrate structure is enhanced, the warpage of the substrate is further suppressed, and the wiring pattern is provided on the surface facing the built-in electronic component mounting surface, thereby enabling high-density wiring.

  According to a fifth aspect of the present invention, a protective film is provided on at least a part of the wiring layer on the insulating layer side and the component mounting pad provided between the first and second insulating substrates. The above-described problems are solved by a component-embedded multilayer printed wiring board.

  As a result, it is possible to avoid leakage and short circuit around the component mounting pad due to solder scattering during mounting of the built-in electronic component, and to increase the vertical symmetry of the substrate structure, thereby further suppressing the warpage of the substrate.

  According to a sixth aspect of the present invention, there is provided a component built-in multilayer printed wiring board in which a wiring layer and a protective film are not formed on the insulating substrate side facing the embedded electronic component. It solves the above problems.

  As a result, the thickness of the substrate can be reduced, the electronic component itself and the height variation generated during mounting can be absorbed, and the destruction of the electronic component due to the contact between the electronic component and the upper insulating substrate can be avoided.

  According to a seventh aspect of the present invention, there is provided a built-in component characterized in that an insulating substrate portion facing the embedded electronic component is opened, and the opening layer is filled with the insulating layer. The above-mentioned problem is solved by a mold multilayer printed wiring board.

  As a result, in addition to the reduction in thickness by removing the conductor and protective film in the electronic component mounting part in the previous section, the thickness of the substrate is further reduced by the thickness of the core material above the electronic component mounting part. Contributes to a significant reduction in thickness.

  The invention according to claim 8 is characterized in that a part or all of the electrodes of the embedded electronic component are connected to the upper layer conductor by an interlayer connection via, and the component-embedded multilayer printed wiring The above problem is solved by a plate.

  As a result, it is possible to directly connect the built-in electronic component mounting surface to the built-in electronic component from the upper surface that does not face the electronic component mounting surface. Transmission loss and delay are reduced by a substrate or the like that uses transmission. In addition, the direct connection eliminates the need for bypass wiring, which has been necessary in the past, and thus the degree of freedom in design is greatly improved.

  According to a ninth aspect of the present invention, at least one electrode of the embedded electronic component is connected to a conductor on the first insulating substrate, and at least other than the electrode connected to the first insulating substrate. One of the electrodes is connected to a conductor on a second insulating substrate, which solves the above problem by a component built-in type multilayer printed wiring board.

  As a result, parts such as component mounting pads, wiring patterns, interlayer connection vias, and the like, which have been conventionally required, are not required, and the wiring area can be expanded and the degree of design freedom can be improved.

  According to a tenth aspect of the present invention, the above-described problem is solved by a component-embedded multilayer printed wiring board, wherein the embedded electronic component is not soldered.

  As a result, the inner layer can be made solder-free, preventing a decrease in connection reliability and contributing to a reduction in the weight of the entire board.

  According to the present invention, it is possible to provide a component built-in type multilayer printed wiring board that prevents warping of a substrate, has a high wiring density, and can be thinned.

  A first embodiment of the present invention will be described with reference to FIG.

  In FIG. 1, P1 is a component built-in type multilayer printed wiring board, and an electronic component 104 is mounted on the component mounting pad 102 of the first insulating substrate 101 provided with a component mounting pad 102 and a wiring circuit on the upper surface using solder 105. In addition, an insulating layer 106 and a second insulating substrate 103 are provided on the electronic component mounting surface of the first insulating substrate 101, and the second insulating substrate 103 is an insulating layer that does not face the electronic component 104. The conductive layer 112 and the protective film 113 are provided on the surface on the 106 side, and the conductive layer 112 and the protective film 113 are not formed on the surface on the insulating layer 106 facing the electronic component 104.

  Here, in FIG. 1, a chip resistor is used as an example of the electronic component 104. However, in the present invention, the electronic component is not limited to the chip resistor, and includes a capacitor, an inductor, a diode, a transistor, All electronic components such as IC and LSI, whether passive or active, are shown. As a matter of course, the component mounting pad 102 uses a component mounting pad having the number of pads, a pad size, and a pad pitch corresponding to the electronic component to be mounted.

  In FIG. 1, “solder 105” is used as an example of means for joining the electronic component 104 to the component mounting pad 102, but means for joining the electronic component to the component mounting pad in the present invention. Is not limited to "solder", but includes electronic components to be mounted regardless of the material and shape, such as conductive adhesive, conductive film, anisotropic conductive adhesive, anisotropic conductive film, etc. A general means for securing to a mounting pad and providing a conductive bond is shown.

  The component-embedded multilayer printed wiring board P1 includes the conductor layer 112 and the protective film 113 on the surface on the insulating layer 106 side where the second insulating substrate 103 does not face the electronic component 104, so that the substrate structure is vertically Symmetrical and warping of the substrate is prevented.

  Further, by providing a wiring pattern on the conductor layer 112, high-density wiring is possible.

  Further, the conductive layer 112 and the protective film 113 are not formed on the surface of the second insulating substrate 103 facing the electronic component 104 on the insulating layer 106 side, and the electronic component 104 is opened to the same size or more. Therefore, the thickness of the substrate can be reduced, and the electronic component itself and the height variation generated during mounting can be absorbed, and the destruction of the electronic component due to the contact between the electronic component and the upper insulating substrate can be avoided.

  Therefore, according to the first embodiment of the present invention, warpage of the substrate is prevented, high-density wiring is possible, and even when the thickness is reduced, destruction of the electronic component due to contact between the electronic component and the upper insulating substrate is avoided. A multilayer printed wiring board with built-in components that can be obtained is obtained.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In FIG. 2A, P2 is a component built-in type multilayer printed wiring board, and the electronic component 214 solders 215 to the component mounting pad 202 of the first insulating substrate 201 provided with the component mounting pad 202 and the wiring circuit on the upper surface. And an insulating layer 216 and a second insulating substrate 203 are provided on the electronic component mounting surface of the first insulating substrate 201, and the second insulating substrate 203 is opposed to the electronic component 214. The insulating layer 216 is provided with a conductor layer 212 and a protective film 213 on the surface thereof, and a portion facing the electronic component 214 is opened to the same size or more as the electronic component 214, and the insulating layer 216 is formed in the opening portion. The insulating resin that has flowed during lamination is filled.

  Furthermore, the electrode 218 of the electronic component 214 in the opened region of the second insulating substrate 203 and the conductor 217 formed on the surface opposite to the insulating layer 216 of the second insulating substrate 203 are provided between the layers. The component mounting pads 202 are not formed below the lower electrode 218 connected by the connection via 204 and connected by the interlayer connection via 204.

  Here, in FIG. 2A, a chip resistor is used as an example of the electronic component 214. However, in the present invention, the electronic component is not limited to the chip resistor, but includes a capacitor, an inductor, and a diode. Electronic devices such as transistors, ICs, LSIs, etc. As a matter of course, the component mounting pad 202 is a component mounting pad having the number of pads, the pad size, and the pad pitch corresponding to the electronic component to be mounted.

  In FIG. 2A, “solder 215” is used as an example of means for joining the electronic component 214 to the component mounting pad 202. In the present invention, the electronic component is joined to the component mounting pad. The means for this is not limited to "solder", but the electronic to be mounted regardless of its material and shape, such as conductive adhesive, conductive film, anisotropic conductive adhesive, anisotropic conductive film, etc. A general means for securing a component to a component mounting pad and providing a conductive bond is shown.

  The component-embedded multilayer printed wiring board P2 has a portion facing the electronic component 214 of the second insulating substrate 203 opened to have the same size or more as the electronic component 214. In addition to thinning by removing the protective film, the substrate can be further thinned by the thickness of the core material above the electronic component mounting portion, and the entire component-embedded substrate can be significantly thinned.

  Further, the electrode 218 of the electronic component 214 in the opened region of the substrate 203 and the conductor 217 formed on the surface opposite to the insulating layer 216 of the second insulating substrate 203 are connected by the interlayer connection via 204. Therefore, it is possible to connect directly to the built-in electronic component from the upper surface that does not face the electronic component mounting surface, the wiring length is optimized, and transmission loss and delay are reduced with a board etc. that uses high-speed transmission In addition, since the detour wiring, which has been necessary in the past, is no longer necessary, the degree of freedom in design is greatly improved.

  Furthermore, the solderless connection can be partially made, the deterioration of the connection reliability can be prevented, the cause of the decrease can be reduced, the weight of the entire substrate can be reduced, and the electrodes connected by the interlayer connection via 204 are also connected. A component mounting pad is not required at the lower part of 218, so that a region used as a conventional component mounting pad can be used as a wiring region, so that the wiring region can be expanded and the degree of design freedom can be improved.

  In addition, no component mounting pad is required under the electrodes connected by the interlayer connection via 204, so that a region used as a conventional component mounting pad can be used as a wiring region. The degree is improved. The electrode 218 and the conductor 217 are connected by the interlayer connection via 204, and the other electrode 219 of the electronic component 214 and the component mounting pad 202 are connected by the solder 215. There is no need for a wiring pattern or a part of an interlayer connection via that is conventionally required when connecting the conductor 202 on the first insulating substrate 201 and the conductor 217 on the second insulating substrate 203 via the electronic component 214. Thus, the wiring area can be expanded and the design flexibility can be improved.

  Further, as shown in FIG. 2B, by connecting all the electrodes 318 of the built-in electronic component 314 using the interlayer connection via 304, an inner layer solderless structure can be obtained. At that time, a conductor layer 312 such as a wiring pattern may be provided under the protective film 313 as long as the protective film 313 covers the portion immediately below the electronic component 314. Further, an adhesive sheet or an adhesive for temporarily fixing the electronic component 314 arranged before the stacking may be provided immediately below the electronic component 314.

  Therefore, according to the second embodiment of the present invention, it is possible to obtain a component-embedded multilayer printed wiring board in which the entire board is significantly reduced in thickness and the degree of freedom of design is greatly improved.

  Next, the manufacturing method of 1st embodiment of this invention is demonstrated using FIGS.

  First, as shown in FIG. 3A, a substrate P4 having conductor layers 2 on both upper and lower surfaces of the insulating layer 1 is prepared. The substrate P4 may be a multilayer substrate.

  Next, a circuit is formed on the conductor layer on the upper surface of the substrate P4 to obtain a substrate P5 as shown in FIG.

  Next, as shown in FIG. 3C, the protective film 3 is formed to obtain the substrate P6.

  Next, as shown in FIG. 4D, the electronic component 4 is mounted using solder 5 to obtain a substrate P7.

  Next, the substrate P8 is manufactured in the same manner as in the steps from FIG. 3A to FIG. 3C, and as shown in FIG. 4E, the portion overlapping the electronic component 4 when being stacked on the substrate P7. Then, the substrate P7 and the substrate P8 are stacked with the insulating layer 6 previously drilled using a router or the like interposed therebetween, and a substrate P9 as shown in FIG. 4F is obtained.

  Next, as shown in FIG. 5G, an interlayer connection via is provided in the outer layer of the substrate P9 to obtain a substrate P10.

  Next, as shown in FIG. 5H, a through hole is provided in the substrate P10 to obtain a substrate P11.

  Next, as shown in FIG. 5 (k), a plating layer 7 is provided on the substrate P11 to obtain a substrate P12.

  Next, as shown in FIG. 6M, circuit formation is performed on the outer layer of the substrate P12 to obtain a substrate P13.

  Next, the component built-in type multilayer printed wiring board P14 as shown in FIG.

  In addition, an insulating layer and a conductor layer are constructed on the outer layer surface of the substrate P13 shown in FIG. 6M instead of the protective film 8 shown in FIG. As a core substrate, the number of constituent layers of the substrate may be increased.

  Next, the manufacturing method of 2nd embodiment of this invention is demonstrated using FIGS.

  First, as shown in FIG. 7A, a substrate P15 having conductor layers 12 on both upper and lower surfaces of the insulating layer 11 is prepared. The substrate P15 may be a multilayer substrate.

  Next, a circuit is formed on the conductor layer on the upper surface of the substrate P15 to obtain a substrate P16 as shown in FIG.

  Next, as shown in FIG. 7C, a protective film 13 is formed to obtain a substrate P17.

  Next, as shown in FIG. 8D, the electronic component 14 is mounted using solder 15 to obtain a substrate P18.

  Next, using the substrate P19 in which the substrate manufactured in the same manner as in the steps from FIG. 8A to FIG. 8 (e), the substrate P18 and the substrate P19 are stacked with the insulating layer 16 previously punched using a router or the like in a portion overlapping the electronic component 14 when stacked on the substrate P18, A substrate P20 as shown in FIG.

  Next, as shown in FIG. 9G, the upper surface of the substrate P20 is subjected to surface polishing so that the surface becomes smooth, thereby obtaining a substrate P21.

  Next, as shown in FIG. 9H, through holes and interlayer connection vias are provided in the substrate P21 to obtain a substrate P22.

  Next, as shown in FIG. 9 (k), a plating layer 17 is provided on the substrate P22 to obtain a substrate P23.

  Next, as shown in FIG. 10 (m), circuit formation is performed on the outer layer of the substrate P23 to obtain a substrate P24.

  Next, a component built-in type multilayer printed wiring board P25 as shown in FIG.

  In addition, on the outer layer surface of the substrate P24 shown in FIG. 10 (m), not the protective film 18 as shown in FIG. 10 (n) but an insulating layer and a conductor layer are constructed, and further buildup is performed. As a core substrate, the number of constituent layers of the substrate may be increased.

  In describing the present invention, the above-described two embodiments and the respective manufacturing methods have been described as examples. However, the configuration of the present invention is not limited to these, and is not limited to these examples. Various modifications are possible within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic cross-sectional explanatory drawing which shows 1st embodiment of this invention. The schematic cross-section explanatory drawing which shows 2nd embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional process explanatory diagram illustrating a manufacturing method according to a first embodiment of the present invention. FIG. 4 is a schematic cross-sectional process explanatory diagram following FIG. 3. FIG. 5 is a schematic cross-sectional process explanatory diagram subsequent to FIG. 4. FIG. 6 is a schematic cross-sectional process explanatory diagram following FIG. 5. Schematic cross-sectional process explanatory drawing which shows the manufacturing method of 2nd embodiment of this invention. FIG. 8 is a schematic cross-sectional process explanatory diagram following FIG. 7. FIG. 9 is a schematic cross-sectional process explanatory diagram following FIG. 8. FIG. 10 is a schematic cross-sectional process explanatory diagram following FIG. 9. FIG. 3 is a schematic cross-sectional explanatory view showing a first conventional example. The schematic cross-section explanatory drawing which shows a 2nd prior art example. Schematic cross-sectional explanatory drawing which shows a 3rd prior art example.

Explanation of symbols

1, 6, 11, 16, 22, 31, 41, 106, 216: insulating layers 2, 12, 112, 212, 312: conductor layers 3, 8, 13, 18, 113, 213, 313: protective film 4, 14, 24, 34, 44, 104, 214, 314: electronic components 5, 15, 105, 215: solder 7, 17: plating layer 21: inner layer wiring substrate 23: single-sided copper foil substrate 25: electronic component mounting substrate 32: Inner via 42: Copper foil 101, 201: First insulating substrate 102, 202: Component mounting pad 103, 203: Second insulating substrate 204, 304: Interlayer connection vias P1-P3, P14, P25-P28: Built-in components Type multilayer printed wiring boards P4 to P13, P15 to P24: substrate

Claims (10)

  A printed wiring board in which an electronic component is embedded in an insulating layer provided between the first and second insulating substrates, wherein the electronic component is formed on one of the first and second insulating substrates A multi-layer printed wiring board with built-in components, which is mounted on a component mounting pad.   2. The component built-in multilayer printed wiring board according to claim 1, wherein the first and second insulating substrates are made of the same material.   3. The component built-in multilayer printed wiring board according to claim 1, wherein the first and second insulating substrates have substantially the same thickness.   4. The component built-in multilayer printed wiring board according to claim 1, wherein wiring layers are provided on the front and back surfaces of the first and second insulating substrates.   5. The protective film is provided on at least a part of the wiring layer on the insulating layer side and the component mounting pad provided between the first and second insulating substrates. The component built-in type multilayer printed wiring board according to the item.   6. The component built-in multilayer printed wiring board according to claim 1, wherein a wiring layer and a protective film are not formed on an insulating substrate side facing the embedded electronic component.   A component-embedded multilayer printed wiring board, wherein an insulating substrate portion facing the embedded electronic component is opened, and the opening layer is filled with the insulating layer.   8. The component built-in multilayer printed wiring board according to claim 7, wherein some or all of the electrodes of the embedded electronic component are connected to the upper layer conductor by an interlayer connection via.   At least one electrode of the embedded electronic component is connected to a conductor on the first insulating substrate, and at least one electrode other than the electrode connected to the first insulating substrate is on the second insulating substrate. 9. The component built-in multilayer printed wiring board according to claim 7 or 8, wherein the component built-in multilayer printed wiring board is connected to a conductor.   The component built-in multilayer printed wiring board according to claim 7, wherein the embedded electronic component is not solder-connected.