JP2012064600A - Multilayer substrate and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lower profile, higher function multilayer substrate having a higher degree of freedom in design, and to provide a method of manufacturing the same.SOLUTION: A multilayer substrate 11 comprises: a core substrate 2; and a first resin layer 12 formed on one main surface 3 of the core substrate 2. A first package component 10 is mounted on a surface conductor formed on the main surface 3 which comes into contact with the core substrate 2 of the first resin layer 12. A second package component 20 is mounted on a surface conductor 35a formed on the main surface 23 facing the main surface 3 which comes into contact with the core substrate 2 of the first resin layer 12. The first package component 10 and the second package component 20 are buried in the first resin layer 12.

Description

  The present invention relates to a multilayer substrate composed of a core substrate and a resin layer and a method for manufacturing the same, and more particularly to a multilayer substrate in which a mounting component is built in a resin layer.

  In recent years, with the reduction in height and functionality of electronic devices, multilayer substrates used in electronic devices are also required to have low height and high functionality, and various multilayer substrates corresponding to this have been developed.

For example, in the multilayer substrate described in Patent Document 1, a resin layer is formed on one main surface of a ceramic multilayer substrate, and a mounting component is mounted inside the resin layer to reduce the height of the substrate. According to Patent Document 1, the advantage of a ceramic multilayer substrate that is strong against heat and moisture and excellent weather resistance, and the resin substrate that has high mechanical strength and low dielectric constant and low signal propagation delay between mounted components A multilayer substrate having both of the advantages of the above can be realized.
JP 2003-188538 A

  However, in the conventional multilayer substrate, a mounting component is mounted on the main surface of a core substrate such as a ceramic multilayer substrate. For this reason, when the resin layer is formed on the main surface of the core substrate so that the mounted component is embedded, there may be a space where the mounted component cannot be mounted inside the resin layer. For example, when a plurality of mounting components are mounted on the main surface of the core substrate, a space may be generated inside the resin layer due to a thickness difference between the mounting components. Therefore, in the conventional multilayer substrate, if it is desired to further mount a mounting component, it is necessary to increase the mounting area or to form a plurality of resin layers as described in Patent Document 1, and to mount the mounting component on each layer, Miniaturization and low profile of the multilayer substrate could not be realized.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-layer substrate and a method for manufacturing the same, which have a low profile and a high function, and which make effective use of the space inside the resin layer and have a higher degree of design freedom.

  In order to solve the above problems, the multilayer substrate of the present invention is formed on both main surfaces of the core substrate, the first resin layer formed on one main surface of the core substrate, and the first resin layer. A plurality of surface conductors, a first mounting component mounted on a surface conductor formed on a main surface of the first resin layer in contact with the core substrate, and a main surface of the first resin layer in contact with the core substrate. A second mounting component mounted on a surface conductor formed on the main surface, and the first mounting component and the second mounting component are embedded in the first resin layer.

  In the multilayer board of the present invention, the first mounting component and the second mounting component have different thicknesses, and are provided at positions facing the first mounting component or the second mounting component with a small thickness. It is preferable to include a third mounting component embedded in the resin layer.

  Moreover, it is preferable that the multilayer substrate of this invention is provided in the inside of the 1st resin layer, and is provided with the interlayer connection conductor which connects the surface conductor formed in both the main surfaces of the 1st resin layer.

  In addition, the multilayer substrate of the present invention includes a surface conductor and / or an interlayer connection conductor that connects the interlayer connection conductor and the surface conductor formed on the main surface facing the main surface contacting the core substrate of the first resin layer. It is preferable.

  Moreover, it is preferable that the multilayer substrate of this invention is equipped with the 2nd resin layer formed in the main surface facing the main surface which contact | connects the core substrate of a 1st resin layer.

  In the multilayer substrate of the present invention, it is preferable that an interlayer connection conductor connected to the second mounting component is formed inside the second resin layer.

  In the multilayer substrate of the present invention, the second mounting component is a bare chip, and the interlayer connection conductor formed inside the second resin layer is connected to the main surface facing the main surface having the terminal electrode of the bare chip. It is preferable that the heat radiator is made.

  In the multilayer substrate of the present invention, it is preferable that the second resin layer is thinner than the first resin layer.

  In addition, the multilayer substrate of the present invention includes a surface conductor formed on a main surface of the second resin layer that is opposed to the main surface in contact with the first resin layer, and a core substrate of the surface conductor and the first resin layer. It is preferable to provide the first resin layer and the second resin layer with surface conductors and / or interlayer connection conductors that connect the surface conductors formed on the main surfaces in contact therewith.

  The present invention is also directed to a method of manufacturing a multilayer substrate as described above.

  The multilayer substrate manufacturing method of the present invention includes a step of preparing a core substrate, a step of forming a surface conductor on one main surface of the core substrate, a step of mounting a first mounting component on the surface conductor, A step of forming a first resin layer on the main surface of the core substrate so that the mounting component is embedded; and a second mounting component from the main surface facing the main surface of the first resin layer contacting the core substrate. Burying and forming a surface conductor connected to the second mounting component.

  Moreover, it is preferable that the manufacturing method of the multilayer board | substrate of this invention mounts a 1st mounting component and a 2nd mounting component by a different method.

  Moreover, it is preferable that the manufacturing method of the multilayer board | substrate of this invention includes the process of forming the interlayer connection conductor which connects the surface conductor formed in both the main surfaces of the 1st resin layer inside the 1st resin layer. .

  In the multilayer substrate manufacturing method of the present invention, the step of forming the interlayer connection conductor inside the first resin layer includes embedding the second mounting component in the first resin layer, It is preferably performed after curing.

  In addition, the method for manufacturing a multilayer board according to the present invention includes a surface conductor and / or an interlayer connection conductor that connects an interlayer connection conductor formed inside the first resin layer and a surface conductor to which the second mounting component is connected. It is preferable to provide the process of forming.

  Moreover, it is preferable that the manufacturing method of the multilayer substrate of this invention includes the process of forming the interlayer connection conductor formed in the inside of the 1st resin layer, the surface conductor, and / or the interlayer connection conductor by plating.

  Moreover, it is preferable that the manufacturing method of the multilayer substrate of this invention is equipped with the process of forming a 2nd resin layer in the main surface facing the main surface which contact | connects the core substrate of a 1st resin layer.

  Moreover, it is preferable that the manufacturing method of the multilayer substrate of this invention is equipped with the process of forming an interlayer connection conductor inside the 2nd resin layer.

  In the method for manufacturing a multilayer board according to the present invention, it is preferable that the interlayer connection conductor is formed so as to be connected to the second mounting component in the step of forming the interlayer connection conductor in the second resin layer.

  The multilayer substrate manufacturing method of the present invention includes a main surface having a bare chip terminal electrode in a step of preparing a bare chip as a second mounting component and a step of forming an interlayer connection conductor inside the second resin layer. It is preferable to form an interlayer connection conductor by forming an interlayer connection conductor hole at a position connected to the main surface opposite to, and filling the interlayer connection conductor hole with a heat conductive paste.

  In addition, the method for manufacturing a multilayer substrate according to the present invention includes a step of forming a surface conductor on a main surface of the second resin layer opposite to the main surface in contact with the first resin layer, and the surface conductor and the first resin layer. It is preferable to include a step of forming a surface conductor and / or an interlayer connection conductor for connecting the surface conductor formed on the main surface in contact with the core substrate on the first resin layer and the second resin layer.

  According to the present invention, the first mounting component mounted on one main surface of the core substrate, and the second mounting component mounted on the main surface facing the main surface contacting the core substrate of the first resin layer, However, since both are embedded in the first resin layer, the height of the multilayer substrate can be reduced. In addition, since mounting components can be mounted from different main surfaces in one layer called the first resin layer, the space inside the resin layer can be used effectively, and the degree of design freedom can be further increased. Furthermore, by using this space to arrange more mounting parts, a highly functional multilayer board is realized.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 is a schematic sectional view showing a multilayer substrate according to an embodiment of the present invention.

  The multilayer substrate 1 includes a ceramic multilayer substrate 2 as a core substrate and a first resin layer 12 formed on one main surface 3 of the ceramic multilayer substrate 2. In addition to the ceramic substrate, a resin substrate may be used as the core substrate.

  The ceramic multilayer substrate 2 is formed by laminating a plurality of ceramic layers 2a to 2c. In each of the ceramic layers 2a to 2c, a surface conductor 5 provided on the surface of each layer and an interlayer connection conductor 7 penetrating each layer in the thickness direction are formed. Circuit elements such as capacitors and inductors can be formed inside the ceramic multilayer substrate 2 by wiring between the surface conductors 5 and the interlayer connection conductors 7.

  A plurality of surface conductors 15 are formed on one main surface 3 of the ceramic multilayer substrate 2, and a plurality of surface conductors 25 are also formed on the opposite main surface 13. A first mounting component 10 is mounted on the surface conductor 15 formed on the one main surface 3 of the ceramic multilayer substrate 2. As the first mounting component 10, an active element such as a semiconductor device such as an IC or a passive element such as a chip resistor can be used. As a mounting method of the first mounting component 10, it may be mounted using solder or a conductive adhesive, or may be mounted by wire bonding. In this example, a multilayer ceramic capacitor was used as the first mounting component 10 and was mounted on the surface conductor 15 by solder reflow.

  Further, the surface conductor 25 formed on the opposite main surface 13 of the ceramic multilayer substrate 2 may be used for connection to a mother board such as a printed circuit board (not shown) or may be used for mounting a mounting component.

  A first resin layer 12 is formed on one main surface 3 of the multilayer ceramic substrate 2. The first resin layer 12 is formed so that the first mounting component 10 is embedded. At this time, the first resin layer 12 may be formed so that a part of the first mounting component 10 is exposed.

  A surface conductor 35 a is formed on the main surface 23 of the first resin layer 12 that faces the main surface 3 that contacts the ceramic substrate 2. The second mounting component 20 is mounted on the surface conductor 35a. As the second mounting component 20, various mounting components can be used similarly to the first mounting component 10. Further, the second mounting component 20 can be mounted by various methods in the same manner as the first mounting component 10. In this example, a bare chip was used as the second mounting component 20, and this was mounted on the surface conductor 35a by wire bonding. Further, a surface conductor 35b for heat dissipation is formed on the main surface 20b opposite to the main surface 20a having the bare-chip terminal electrodes. The surface conductors 35a and 35b are embedded in the first resin layer 12.

  Thus, the multilayer substrate 1 includes the first mounting component 10 mounted on the surface conductor 15 formed on the main surface 3 in contact with the ceramic multilayer substrate 2 of the first resin layer 12, and the first resin layer 12. A plurality of mounting components with the second mounting component 20 mounted on the surface conductor 35a formed on the main surface 23 opposed to the main surface 3 in contact with the ceramic multilayer substrate 2 are different main layers of the first resin layer 12. It is mounted on each of the surfaces 3 and 23 and embedded in the first resin layer 12. As a result, it is not necessary to form a plurality of resin layers for mounting the second mounting component, so that the multilayer substrate 1 can be reduced in height.

  As described above, since the mounting components can be mounted from both main surfaces of the first resin layer 12, the space inside the first resin layer 12 can be effectively used, and more mounting components can be mounted than before. Therefore, the multi-layer substrate 1 can be highly functionalized. Moreover, since the space inside the first resin layer can be used effectively, the degree of freedom in design can be increased.

  Further, as shown in FIG. 1, when the first mounting component 10 is thicker than the second mounting component 20, the third mounting component 30 is mounted at a position facing the thin second mounting component. Also good. In this case, the third mounting component 30 is mounted on the surface conductor 15 formed on the one main surface 3 of the ceramic multilayer substrate 2 and embedded in the first resin layer 12. When the second mounting component 20 is thicker than the first mounting component 10, the third mounting component 30 may be mounted at a position facing the thin first mounting component. In this case, the third mounting component 30 is mounted on the surface conductor 35 a formed on the main surface 23 of the first resin layer 12 that faces the main surface 3 that contacts the ceramic multilayer substrate 2, and is mounted on the first resin layer 12. Buried. Thereby, even when the thicknesses of the mounted components are different, the space inside the first resin layer 12 can be used effectively.

  As shown in FIG. 1, an interlayer connection conductor 17 that connects the surface conductors 15 and 35 formed on both main surfaces of the first resin layer is formed inside the first resin layer 12. . Thereby, for example, the surface conductor 35 a formed on the main surface 23 of the first resin layer 12 and the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2 can be connected. Thus, since the surface conductor 35a on which the second mounting component 20 is mounted and the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2 are connected, signal processing of the second mounting component 20 is performed. Can be performed by the ceramic multilayer substrate 2. Since the ceramic multilayer substrate 2 is suitable for fine wiring, the wiring can be concentrated on the ceramic multilayer substrate 2 without complicating the wiring inside the first resin layer 12. This is effective in realizing a multi-layer board and a multi-layer module with a lower profile and higher function.

  The surface conductor 35 a on which the second mounting component 20 is mounted is in contact only with the side surface portion of the interlayer connection conductor 17. Therefore, it is desirable to provide the surface conductor 35c that connects the surface conductor 35a and the interlayer connection conductor 17 because the connection reliability between the surface conductor 35a and the interlayer connection conductor 17 can be improved. Here, the surface conductor 35c further forms a resin layer having an interlayer connection conductor on the main surface 23 of the first resin layer, and this interlayer connection conductor reinforces the connection between the interlayer connection conductor 17 and the surface conductor 35a. May be.

  Further, as shown in FIG. 2, a second resin layer 22 may be formed on the main surface 23 of the first resin layer 12. Thereby, wiring can be formed in the 2nd resin layer 22, and the multilayer substrate 11 made highly functional is realizable. In addition, as shown in FIG. 2, not the surface conductor 25 formed on the main surface 13 of the ceramic multilayer substrate 2 but the surface conductor 45 formed on the main surface 33 of the second resin layer 22 is connected to the motherboard. In this case, the second resin layer 22 can function as an insulating layer between the second mounting component 20 and the motherboard. In this case, the fourth mounting component 40 may be mounted on the surface conductor 25 formed on the main surface 13 of the ceramic multilayer substrate 2. Thereby, the multilayer substrate 11 can be further enhanced in function.

  Furthermore, as shown in FIG. 2, an interlayer connection conductor 27 that penetrates the second resin layer 22 in the thickness direction may be formed inside the second resin layer 22. When the second mounting component 20 is a bare chip, specifically, a bare IC as in this embodiment, when the interlayer connection conductor 27 is connected to the main surface 20b facing the main surface 20a having the terminal electrode of the bare chip, Since the interlayer connection conductor 27 functions as a heat radiator and the heat generated from the bare chip can be released to the mother board, a multilayer board and a multilayer module having excellent heat dissipation can be realized. At this time, a heat radiating surface conductor 35b for connection to the interlayer connection conductor 27 is formed on the main surface 20b of the bare chip.

  The second resin layer 22 is preferably thinner than the first resin layer 12. This is because the multilayer substrate 11 can be reduced in height, and the shorter the interlayer connection conductor 27 serving as a heat radiator, the better the heat dissipation.

  Further, as shown in FIG. 2, a surface conductor 45 is formed on the main surface 33 of the second resin layer 22, and the surface conductor 45 and the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2 are connected. An interlayer connection conductor 37 may be formed. This is for connecting the surface conductor 45 used for connection to the mother board and the surface conductor 15 formed on the main surface 3 of the ceramic multilayer board 2 when connecting the multilayer board 11 and the mother board. The interlayer connection conductor 37 only needs to connect the surface conductor 45 and the surface conductor 15, and one interlayer connection conductor 37 that penetrates the first resin layer 12 and the second resin layer 22 in the thickness direction. Alternatively, the interlayer connection conductor of the first resin layer 12 and the interlayer connection conductor of the second resin layer 22 may be connected by a surface conductor.

  Next, a method for manufacturing a multilayer substrate according to the present embodiment will be described with reference to FIGS.

  3 to 9 are schematic process diagrams showing a method of manufacturing the multilayer substrate according to FIG.

  First, a ceramic multilayer substrate 2 as a core substrate as shown in FIG. 3 is prepared. The ceramic multilayer substrate 2 is produced as follows.

A ceramic slurry is applied onto the carrier film by a doctor blade method or the like to form a ceramic green sheet. The ceramic slurry is formed by appropriately mixing ceramic powder such as Al ₂ O ₃ and a binder, a dispersant, a solvent, and the like. This ceramic green sheet becomes ceramic layers 2a to 2c after firing.

  The ceramic green sheet is provided with a hole for an interlayer connection conductor that penetrates the ceramic green sheet in the thickness direction with a laser or a mold. The interlayer connection conductor hole is filled with a conductive paste in which a metal powder mainly composed of Ag or Cu, a resin, a solvent, or the like is mixed. The conductive paste filled in the hole for the interlayer connection conductor becomes the interlayer connection conductor 7 after firing. The conductive paste is also applied on the ceramic green sheet so as to form a desired circuit pattern. The conductive paste applied on the ceramic green sheet becomes the surface conductors 5, 15, 25 after firing. As a method for filling and applying the conductive paste, various methods such as screen printing, electrophotography, and ink jet method can be used.

  A plurality of ceramic green sheets are laminated and pressure-bonded as necessary, and fired in a predetermined atmosphere of about 800 to 1000 ° C. to obtain a ceramic multilayer substrate 2 including the interlayer connection conductor 7 and the surface conductors 5, 15 and 25. . The surface conductors 15 and 25 formed on both main surfaces 3 and 13 of the ceramic multilayer substrate 2 are plated with Ni, Au or the like as necessary.

  Next, the first mounting component 10 and the third mounting component 30 are mounted on the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2. In the present embodiment, solder is printed on the surface conductor 15, and after mounting the first mounting component 10 and the third mounting component 30, the solder is melted in a reflow furnace, and the first mounting component 10 and The third mounting component 30 and the surface conductor 15 were fixed. The first mounting component 10 and the third mounting component 30 may be mounted on the surface conductor 15 by wire bonding. However, it is desirable to mount the first mounting component 10 and the third mounting component 30 by the same mounting method. When mounting parts with different mounting methods on the same main surface, the mounting process becomes complicated, and the mounting ratio of the mounting parts that have been mounted earlier will cause a connection failure in the subsequent mounting process, resulting in a higher failure rate such as mounting defects. Because. The fourth mounting component 40 may be mounted on the surface conductor 25 formed on the opposite main surface 13 of the ceramic multilayer substrate 2.

  Next, a semi-cured first resin layer 12 is formed on the main surface 3 of the ceramic multilayer substrate 2. At this time, the first resin layer 12 is formed to a thickness such that the first mounting component 10 and the third mounting component 30 are embedded. When mounting the fourth mounting component 40, a resin layer may be formed on the main surface 13 of the ceramic multilayer substrate 2 so as to cover the fourth mounting component 40. The semi-cured resin layer refers to a B stage state or a prepreg.

The first resin layer 12, it is possible to use epoxy, phenol, a mixture of an inorganic filler such as cyanate thermosetting resin and Al ₂ O _3, such as, SiO _2, TiO _2. These mixtures are formed as a semi-cured resin sheet and laminated on the main surface 3 of the ceramic multilayer substrate 2.

  Next, the second mounting component 20 is embedded in the main surface 23 of the first resin layer 12 facing the main surface 13 of the ceramic multilayer substrate 2 to form a surface conductor 35a on which the second mounting component is mounted. To do.

  In this embodiment, first, as shown in FIG. 3, a copper foil patterned to form the surface conductors 35a and 35b is formed on a carrier film 8 such as a PET film by a method such as pasting. . And the bare chip which is the 2nd mounting components 20 is mounted on the copper foil used as the surface conductor 35a by wire bonding. Note that a copper foil serving as a heat dissipating surface conductor 35b is formed on the main surface 20b opposite to the main surface 20a having the bare-chip terminal electrodes.

  Next, the carrier film 8 is laminated and pressure-bonded to the main surface 23 of the first resin layer 12 in a semi-cured state, and then the carrier film is peeled off. As a result, the second mounting component 20 is embedded in the first resin layer 12, and the patterned copper foil is transferred to the main surface 23 of the first resin layer 12 to form the surface conductor 35a.

  Note that the step of embedding the second mounting component 20 in the first resin layer 12 and the step of forming the surface conductor 35a on which the second mounting component 20 is mounted are not necessarily performed simultaneously. For example, the surface conductors 35a and 35b may be formed after the second mounting component 20 is formed on the carrier film 8 with an adhesive or the like, embedded in the first resin layer 12, and the carrier film 8 is peeled off. .

  Thus, in this embodiment, the first mounting component 10 mounted by solder reflow and the second mounting component 20 mounted by wire bonding are mounted from different main surfaces 3 and 23 of the first resin layer 12. Can do. Therefore, the manufacturing process becomes easier and the defect rate can be reduced as compared with the case where mounting components having different mounting methods are mounted on the same main surface. In addition, when mounting components are mounted from both main surfaces of the first resin layer in this way, it is not necessary to form a plurality of resin layers when mounting components having different mounting methods, and the multilayer substrate 11 can be further reduced. Can be turned upside down.

  Next, the multilayer substrate 11 is heat-treated, the thermosetting resin contained in the resin sheet is cured, and the first resin layer 12 that has been in a semi-cured state is cured.

  Thereafter, as shown in FIG. 4, an interlayer connection hole 17a is formed by a laser or the like. The interlayer connection conductor hole 17a may be formed when the first resin layer 12 is in a semi-cured state, but is preferably formed after the first resin layer 12 is cured. In the case of the semi-cured state, the diameter of the hole may be larger than a desired size when forming the interlayer connection conductor hole 17a, and the hole may be deformed at the time of curing. Here, the interlayer connection conductor hole 17 a is formed on the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2 and the main surface 23 of the first resin layer 12, and is connected to the second mounting component 20. It is formed so that it can be connected to the surface conductor 35a.

  Next, the interlayer connection conductor is formed by filling the interlayer connection conductor hole 17a with a conductive paste by screen printing or the like. As the conductive paste, a mixture of metal particles such as Ag and Cu and a thermosetting resin such as epoxy, phenol and cyanate can be used.

  And the thermosetting resin contained in the interlayer connection conductor is cured by heat-treating the multilayer substrate 11.

  When the surface conductor 35a is formed on the main surface 23 of the first resin layer 12 and the interlayer connection conductor hole 17a is formed by a laser or the like, the interlayer connection conductor formed in the surface conductor 35a and the first resin layer is formed. Means contact only on the side surface, and there is a risk that connection reliability is weak. Therefore, as shown in FIG. 5, it is preferable that a surface conductor 35 c for connecting the surface conductor 35 a and the interlayer connection conductor 17 is further formed on the main surface 23 of the first resin layer 12. Here, if the interlayer connection conductor 17 and the surface conductor 35c are formed by plating, they can be formed at the same time, so that the manufacturing process can be facilitated. Further, a resin layer having an interlayer connection conductor may be further formed on the main surface 23 of the first resin layer, and the connection between the interlayer connection conductor 17 and the surface conductor 35a may be reinforced by this interlayer connection conductor.

  In this way, the multilayer substrate 11 and the multilayer module that perform the signal processing of the second mounting component 20 connected to the surface conductor 35a formed on the main surface 23 of the first resin layer 12 by the ceramic multilayer substrate 2 are provided. Can be manufactured.

  As shown in FIG. 6, an interlayer connection conductor 17 may be formed in the first resin layer 12 before the second mounting component 20 is embedded in the first resin layer 12. In this case, the surface conductor 35a and the interlayer connection conductor 17 are connected not only on the side surface but also on the main surface. Therefore, there is no fear that these connection reliability is weak, which is preferable in that it is not necessary to form a surface conductor or an interlayer connection conductor to reinforce the connection. At this time, an interlayer connection conductor hole for forming the interlayer connection conductor 17 is formed in the semi-cured first resin layer 12. This is because the second mounting component 20 cannot be embedded in the first resin layer 12 after curing.

  Moreover, as shown in FIG. 7, the interlayer connection conductor 17 may be formed at the stage of the resin sheet before lamination. In addition, for the second mounting component 20, the resin sheet 12 a may be laminated on the main surface 3 of the ceramic multilayer substrate 2 after the second mounting component 20 is embedded in the resin sheet 12 a.

  The first resin layer 12 may be formed by making the mixture of the thermosetting resin and the inorganic filler described above into a paste and dropping it on the main surface 3 of the ceramic multilayer substrate 2.

  Next, as shown in FIG. 8, the second resin layer 22 is formed on the main surface 13 of the first resin layer 12 facing the main surface 3 in contact with the ceramic multilayer substrate 2.

  As the second resin layer 22, as in the first resin layer 12, a semi-cured resin sheet can be used. Specifically, similarly to the first resin layer 12, a second resin layer 22 is obtained by laminating a semi-cured resin sheet on the main surface 23 of the first resin layer 12, and then curing the resin sheet. Form.

  Here, the second resin layer 22 is preferably formed thinner than the first resin layer 12 in order to reduce the height of the multilayer substrate 11 and to dissipate heat from the second mounting component 20 described later.

  Next, as shown in FIG. 9, interlayer connection conductors 27 and 37 are also formed inside the semi-cured second resin layer 22.

  Here, the interlayer connection conductor 27 is located at a position where it can be connected to the surface conductor 35b formed on the main surface 20b opposite to the main surface 20a having the terminal electrode of the bare chip that is the second mounting component 20. 22 is formed so as to penetrate in the thickness direction.

  On the other hand, the interlayer connection conductor 37 penetrates the second resin layer 22 and the first resin layer 12 in the thickness direction at a position connected to the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2. To form.

  Specifically, first, the semi-cured second resin layer 22 is formed on the main surface 23 of the first resin layer 12. Thereafter, the interlayer connecting conductor 27 penetrates the semi-cured second resin layer 22 in the thickness direction, and the interlayer connecting conductor 37 is cured with the semi-cured second resin layer 22. A hole for an interlayer connection conductor is formed by a laser or the like so as to penetrate through the first resin layer 12 in the thickness direction.

  Next, the interlayer connection conductor hole to be the interlayer connection conductor 27 is filled with a heat conductive paste, and the interlayer connection conductor hole to be the interlayer connection conductor 37 is filled with a conductive paste by a method such as screen printing. Here, the same thing as a conductive paste can be used for a heat conductive paste.

  Next, a copper foil patterned to form the surface conductor 45 is formed on the carrier film 8, and this is laminated and pressure-bonded to the main surface 33 of the second resin layer 22, and the carrier film is peeled off. The surface conductor 45 is formed on the main surface 33 of the second resin layer 22.

  Then, the second resin layer 22 in a semi-cured state and the heat conductive paste and the conductive paste filled in the hole for the interlayer connection conductor are heated to cure them, and the second resin layer 22 in the cured state is cured. And the multilayer substrate 11 is produced by forming the interlayer connection conductors 27 and 37. Note that heat treatment is preferably performed by thermocompression when forming the surface conductor 45 because the manufacturing process can be simplified.

  The interlayer connection conductor 27 manufactured in this way is used as a heat radiator for releasing heat generated from the bare chip to the mother board. The second resin layer 22 is preferably formed thinner than the first resin layer 12. This is because the interlayer connection conductor 27 can be shortened to further improve the heat dissipation.

  The interlayer connection conductor 37 connects the surface conductor 45 used for connection with the motherboard and the surface conductor 15 formed on the main surface 3 of the ceramic multilayer substrate 2 when connecting the multilayer substrate 11 and the motherboard. Used for. Therefore, the interlayer connection conductor 37 only needs to connect the surface conductor 45 and the surface conductor 15. For example, an interlayer connection conductor is formed in the first resin layer 12 at a position where it can be connected to the surface conductor 15, and the interlayer connection conductor formed in the second resin layer 22 at a position different from this is connected to the first resin layer 12. The surface conductor 45 may be connected to the surface conductor formed on the main surface 23 of the resin layer 12.

  Note that the hole for the interlayer connection conductor formed inside the second resin layer 22 may be formed in the state of the resin sheet before lamination as in the case of the first resin layer 12.

  In addition, after the second resin layer 22 is cured, the hole for the interlayer connection conductor may be formed. However, since the copper foil used as the surface conductor 45 cannot be adhere | attached on the 2nd resin layer 22 after hardening, it is necessary to laminate | stack the resin layer of a semi-hardened state further.

  Similarly to the case of the first resin layer 12, the second resin layer 22 may be formed by dropping a paste-like resin onto the main surface 23 of the first resin layer 12 and curing it. Good.

  3 to 9, a single multilayer substrate is illustrated, but actually, a plurality of multilayer substrates are produced as an aggregate substrate, and this is divided by a chocolate break method or a dicer cutting method. As a result, individual multilayer substrates can be obtained.

It is a schematic sectional drawing which shows the multilayer substrate based on the Example of this invention. It is a schematic sectional drawing which shows the other multilayer substrate based on the Example of this invention. FIG. 4 is a schematic process diagram illustrating a method for manufacturing a multilayer substrate according to an embodiment of the present invention, and is a diagram illustrating a process of embedding a second mounting component after forming a first resin layer on the main surface of a core substrate. . It is a schematic process drawing which shows the manufacturing method of the multilayer board | substrate which concerns on the Example of this invention, and is a figure which shows the process of forming the hole for interlayer connection conductors in the inside of the 1st resin layer. It is a schematic process drawing which shows the manufacturing method of the multilayer board | substrate which concerns on the Example of this invention, and connects the interlayer connection conductor formed in the inside of the 1st resin layer, and the surface conductor in which the 2nd mounting component was mounted. It is a figure which shows the process of forming a surface conductor. It is a schematic process drawing which shows the manufacturing method of the multilayer substrate based on the Example of this invention, and is a figure which shows the other method of forming an interlayer connection conductor inside the 1st resin layer. It is a schematic process drawing which shows the manufacturing method of the multilayer substrate based on the Example of this invention, and is a figure which shows the other method of forming an interlayer connection conductor inside the 1st resin layer. It is a schematic process drawing which shows the manufacturing method of the multilayer board | substrate which concerns on the Example of this invention, and is a figure which shows the process of forming a 2nd resin layer. It is a schematic process drawing which shows the manufacturing method of the multilayer board | substrate which concerns on the Example of this invention, The process of forming an interlayer connection conductor in the inside of a 2nd resin layer and a surface conductor in the main surface of a 2nd resin layer is shown. FIG.

Explanation of symbols

1,11 Multilayer substrate 2 Ceramic multilayer substrate (core substrate)
3, 13, 23, 33 Main surface 5, 15, 25, 35, 45 Surface conductor 7, 17, 27 Interlayer connection conductor 10 First mounting component 12 First resin layer 20 Second mounting component 22 Second mounting Resin layer 30 Third mounting component 37 Surface conductor and / or interlayer connection conductor

Claims (20)

A core substrate;
A first resin layer formed on one main surface of the core substrate;
A plurality of surface conductors formed on both main surfaces of the first resin layer;
A first mounting component mounted on the surface conductor formed on the main surface of the first resin layer in contact with the core substrate;
A second mounting component mounted on the surface conductor formed on the main surface facing the main surface of the first resin layer in contact with the core substrate;
With
The multilayer board according to claim 1, wherein the first mounting component and the second mounting component are embedded in the first resin layer. The first mounting component and the second mounting component have different thicknesses,
The third mounting component is provided at a position facing the first mounting component or the second mounting component having a small thickness, and is embedded in the first resin layer. The multilayer substrate described.   3. The interlayer connection conductor according to claim 1, further comprising an interlayer connection conductor that is formed inside the first resin layer and connects the surface conductors formed on both main surfaces of the first resin layer. Multilayer board.   A surface conductor and / or an interlayer connection conductor for connecting the interlayer connection conductor and the surface conductor formed on the main surface of the first resin layer facing the main surface in contact with the core substrate are provided. The multilayer substrate according to claim 3.   5. The multilayer substrate according to claim 1, further comprising: a second resin layer formed on a main surface of the first resin layer facing a main surface in contact with the core substrate.   6. The multilayer substrate according to claim 5, wherein an interlayer connection conductor connected to the second mounting component is formed inside the second resin layer. The second mounting component is a bare chip;
The said interlayer connection conductor formed in the inside of the said 2nd resin layer is a heat radiator connected to the main surface facing the main surface which has the terminal electrode of the said bare chip, It is characterized by the above-mentioned. Multilayer board.   The multilayer substrate according to claim 5, wherein the second resin layer is thinner than the first resin layer. A surface conductor formed on a main surface of the second resin layer facing a main surface in contact with the first resin layer;
A surface conductor and / or an interlayer connection conductor for connecting the surface conductor and the surface conductor formed on the main surface of the first resin layer in contact with the core substrate is used as the first resin layer and the second resin. The multilayer substrate according to claim 5, further comprising a layer. Preparing a core substrate; and
Forming a surface conductor on one main surface of the core substrate;
Mounting a first mounting component on the surface conductor;
Forming a first resin layer on the main surface of the core substrate so that the first mounting component is embedded;
Embedding a second mounting component from a main surface facing the main surface of the first resin layer in contact with the core substrate, and forming a surface conductor connected to the second mounting component;
A method for manufacturing a multilayer substrate comprising:   The method for manufacturing a multilayer board according to claim 10, wherein the first mounting component and the second mounting component are mounted by different methods.   12. The method according to claim 10, further comprising forming an interlayer connection conductor that connects the surface conductors formed on both main surfaces of the first resin layer inside the first resin layer. A method for manufacturing a multilayer substrate.   The step of forming the interlayer connection conductor in the first resin layer is performed after the second mounting component is embedded in the first resin layer and the first resin layer is cured. The method for producing a multilayer substrate according to claim 12, wherein:   14. The multilayer according to claim 12, comprising a step of forming a surface conductor and / or an interlayer connection conductor that connects the interlayer connection conductor and the surface conductor to which the second mounting component is connected. A method for manufacturing a substrate.   The method for producing a multilayer substrate according to claim 14, wherein the interlayer connection conductor, the surface conductor and / or the interlayer connection conductor are formed by plating.   The method for manufacturing a multilayer substrate according to any one of claims 10 to 15, further comprising a step of forming a second resin layer on a main surface of the first resin layer opposite to a main surface in contact with the core substrate.   The method for manufacturing a multilayer substrate according to claim 16, further comprising a step of forming an interlayer connection conductor inside the second resin layer.   The multilayer board according to claim 17, wherein in the step of forming an interlayer connection conductor inside the second resin layer, the interlayer connection conductor is formed so as to be connected to the second mounting component. Manufacturing method. Preparing a bare chip as the second mounting component;
In the step of forming an interlayer connection conductor inside the second resin layer, an interlayer connection conductor hole is formed at a position connected to the main surface opposite to the main surface having the terminal electrode of the bare chip, and the interlayer connection 19. The method for manufacturing a multilayer board according to claim 18, wherein the interlayer connection conductor is formed by filling a conductor hole with a heat conductive paste. Forming a surface conductor on a main surface of the second resin layer opposite to the main surface in contact with the first resin layer;
A surface conductor and / or an interlayer connection conductor for connecting the surface conductor and the surface conductor formed on the main surface of the first resin layer in contact with the core substrate is used as the first resin layer and the second resin. The method for producing a multilayer substrate according to claim 16, further comprising a step of forming a layer.

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