Laminated substrate

Abstract

Provided is a laminated substrate in which a metal compound formed between a conductor part provided in a ceramic layer and an interlayer connection conductor provided in a thermoplastic resin layer does not easily break even when the laminated substrate is heated. This laminated substrate (1) is provided with a first thermoplastic resin layer having a first main surface (21a) and a second main surface (21b) facing the first main surface (21a), and having a via hole (21h) penetrating from the first main surface to the second main surface, and a ceramic layer (11) disposed so as to be in contact with the first main surface (21a), and an interlayer connection conductor (50) disposed in the via hole (21h). A conductor part (31) connected to the interlayer connection conductor (50) is formed on the ceramic layer (11), an intermetallic compound (61) is formed between the interlayer connection conductor (50) and the conductor part (31), ceramic particles (70) are present inside the intermetallic compound (61), and some of the ceramic particles (70) are first ceramic particles (71) that are in contact with both the intermetallic compound (61) and the conductor part (31).

Description

Technical Field

[0001] The present invention relates to a laminate substrate. Background Art

[0002] Conventionally, module components using multilayer substrates with built-in passive components have been put into practical use. For example, a DCDC converter module is known in which a switch IC (integrated circuit) chip and a chip capacitor are mounted on a multilayer substrate with built-in coils as the passive components.

[0003] As a multilayer substrate used in such a module component, a multilayer substrate formed by stacking ceramic substrates is known. In the multilayer substrate formed by stacking ceramic substrates, warping of the ceramic substrates sometimes occurs. In order to solve such a problem, Patent Document 1 discloses a stacked substrate (module component) in which a substrate (thermoplastic resin layer) made of a thermoplastic resin is stacked on a multilayer substrate formed by stacking ceramic substrates.

[0004] That is, Patent Document 1 discloses a module component, comprising: a ceramic multilayer substrate having a built-in passive component and having a first terminal electrode and a second terminal electrode connected to the passive component on one main surface and the other main surface, respectively; a first thermoplastic resin layer provided on the one main surface of the ceramic multilayer substrate and having a first wiring connected to the first terminal electrode and a first soldering pad for mounting a surface mounted component; a second thermoplastic resin layer provided on the other main surface of the ceramic multilayer substrate and having a second wiring connected to the second terminal electrode and a second soldering pad serving as a connection terminal to a motherboard; and a second thermoplastic resin layer provided on the first thermoplastic resin layer. The ceramic multilayer substrate is a substrate using a non-glass-based low-temperature co-fired ceramic material, and the first terminal electrode of the ceramic multilayer substrate and the interlayer conductor provided on the first thermoplastic resin layer, and the second terminal electrode of the ceramic multilayer substrate and the interlayer conductor provided on the second thermoplastic resin layer are respectively bonded by liquid phase diffusion bonding.

[0005] In Patent Document 1, terminal electrodes provided on a ceramic multilayer substrate and interlayer conductors provided on a thermoplastic resin layer are bonded by liquid phase diffusion bonding (Transient Liquid Phase Diffusion Bonding).

[0006] Patent Document 2 discloses an interlayer connection conductor connected to a conductor wiring layer, and discloses that an intermetallic compound layer containing an intermetallic compound is formed between the conductor wiring layer and the interlayer connection conductor.

[0007] The intermetallic compound layer is formed by heating a metal such as Sn or a Sn alloy constituting the interlayer connection conductor to melt it and reacting it with a metal (for example, Cu) constituting the conductor wiring layer. That is, the intermetallic compound layer is formed during liquid phase diffusion bonding.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent No. 6819668

[0011] Patent Document 2: International Publication No. 2019 / 003729 Summary of the invention

[0012] In the laminated substrate (module component) described in Patent Document 1, an intermetallic compound layer as disclosed in Patent Document 2 is also formed between a conductor portion (terminal electrode) provided on a ceramic layer and an interlayer connection conductor (interlayer conductor) provided on a thermoplastic resin layer.

[0013] The conductor portion formed in the ceramic layer, the interlayer connection conductor provided in the thermoplastic resin layer, and the intermetallic compound layer have different linear expansion coefficients, and therefore thermal stress is likely to be generated between them.

[0014] In particular, since the ductility of the intermetallic compound is low, there is a problem that it is difficult for the intermetallic compound to absorb thermal stress, and the intermetallic compound is prone to fracture.

[0015] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a laminated substrate in which a metal compound formed between a conductor portion provided in a ceramic layer and an interlayer connection conductor provided in a thermoplastic resin layer is not easily broken even when heated.

[0016] The laminated substrate of the present invention comprises a first thermoplastic resin layer and a ceramic layer, wherein the first thermoplastic resin layer comprises a first main surface and a second main surface opposite to the first main surface, and has a via hole penetrating from the first main surface to the second main surface, the ceramic layer is arranged in contact with the first main surface, an interlayer connection conductor is arranged in the via hole, a conductor portion connected to the interlayer connection conductor is formed in the ceramic layer, an intermetallic compound is formed between the interlayer connection conductor and the conductor portion, ceramic particles exist inside the intermetallic compound, and a part of the ceramic particles are first ceramic particles in contact with both the intermetallic compound and the conductor portion.

[0017] According to the present invention, it is possible to provide a laminate substrate in which a metal compound formed between a conductor portion provided in a ceramic layer and an interlayer connection conductor provided in a thermoplastic resin layer is unlikely to break even when heated. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A It is a cross-sectional view schematically showing an example of a multilayer substrate according to the first embodiment of the present invention.

[0019] Figure 1B yes Figure 1A An enlarged view of the dotted line portion.

[0020] Figure 2 This is a cross-sectional view schematically showing an example of the vicinity of the interlayer connection conductor in another example of the multilayer substrate according to the first embodiment of the present invention.

[0021] Figure 3 This is a process diagram schematically showing an example of an LTCC green sheet preparation process in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0022] Figure 4A This is a process diagram schematically showing an example of a via hole filling step of an LTCC green sheet in the method for manufacturing a laminated substrate according to the first embodiment of the present invention.

[0023] Figure 4B This is a process diagram schematically showing an example of a via hole filling step of an LTCC green sheet in the method for manufacturing a laminated substrate according to the first embodiment of the present invention.

[0024] Figure 5 This is a process diagram schematically showing an example of an electrode pattern forming step of an LTCC green sheet in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0025] Figure 6 This is a process diagram schematically showing an example of a LTCC green sheet lamination step in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0026] Figure 7 This is a process diagram schematically showing an example of a firing step of an LTCC green sheet laminate in the method for producing a laminate substrate according to the first embodiment of the present invention.

[0027] Figure 8 This is a process diagram schematically showing an example of a thermoplastic resin layer preparation step in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0028] Fig. 9A This is a process diagram schematically showing an example of a step of forming an electrode pattern of a thermoplastic resin layer in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0029] Fig. 9B This is a process diagram schematically showing an example of a step of forming an electrode pattern of a thermoplastic resin layer in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0030] Fig. 10A This is a process diagram schematically showing an example of a via hole filling step of a thermoplastic resin layer in the method for manufacturing a laminated substrate according to the first embodiment of the present invention.

[0031] Fig. 10B This is a process diagram schematically showing an example of a via hole filling step of a thermoplastic resin layer in the method for manufacturing a laminated substrate according to the first embodiment of the present invention.

[0032] Fig.11 This is a process diagram schematically showing an example of a lamination step of a thermoplastic resin layer in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0033] Fig. 12A This is a process diagram schematically showing an example of a lamination step of a plurality of ceramic layers and a plurality of thermoplastic resin layers in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0034] Fig. 12B This is a process diagram schematically showing an example of a lamination step of a plurality of ceramic layers and a plurality of thermoplastic resin layers in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0035] Fig.13A This is an explanatory diagram schematically showing an example of connecting an interlayer connection conductor and a first electrode by liquid phase diffusion bonding.

[0036] Fig. 13B This is an explanatory diagram schematically showing an example of connecting an interlayer connection conductor and a first electrode by liquid phase diffusion bonding.

[0037] Fig. 13C This is an explanatory diagram schematically showing an example of connecting an interlayer connection conductor and a first electrode by liquid phase diffusion bonding.

[0038] Fig.13D This is an explanatory diagram schematically showing an example of connecting an interlayer connection conductor and a first electrode by liquid phase diffusion bonding.

[0039] Fig.14 This is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a laminate substrate according to a second embodiment of the present invention.

[0040] Fig.15This is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a multilayer substrate according to a third embodiment of the present invention.

[0041] Fig.16 This is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a laminate substrate according to a fourth embodiment of the present invention.

[0042] Fig.17 It is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a laminate substrate according to a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0043] Hereinafter, the laminated substrate of the present invention will be described.

[0044] However, the present invention is not limited to the following configurations, and can be appropriately modified and applied within the scope of the present invention. It should be noted that a configuration in which two or more of the preferred configurations of the present invention described below are combined also constitutes the present invention.

[0045] The laminated substrate of the present invention comprises a first thermoplastic resin layer and a ceramic layer, wherein the first thermoplastic resin layer comprises a first main surface and a second main surface opposite to the first main surface, and has a via hole penetrating from the first main surface to the second main surface, the ceramic layer is arranged in contact with the first main surface, an interlayer connection conductor is arranged in the via hole, a conductor portion connected to the interlayer connection conductor is formed in the ceramic layer, an intermetallic compound is formed between the interlayer connection conductor and the conductor portion, ceramic particles exist inside the intermetallic compound, and a part of the ceramic particles are first ceramic particles in contact with both the intermetallic compound and the conductor portion.

[0046] In the multilayer substrate of the present invention, ceramic particles exist inside the intermetallic compound.

[0047] Therefore, the difference between the linear expansion coefficient of the intermetallic compound and the linear expansion coefficient of the conductor portion formed in the ceramic layer can be reduced. As a result, the thermal stress applied to the intermetallic compound can be reduced. Therefore, the intermetallic compound can be prevented from being broken due to the thermal stress.

[0048] In addition, when manufacturing the multilayer substrate of the present invention, the interlayer connection conductor is connected to the conductor portion by liquid phase diffusion bonding. At this time, the intermetallic compound is formed by the reaction of the conductor portion with the liquid phase component of the interlayer connection conductor.

[0049] The presence of ceramic particles inside the intermetallic compound means that when manufacturing the laminated substrate of the present invention, the conductor portion contains ceramic particles. If the conductor portion contains ceramic particles, the contact area between the conductor portion and the liquid phase component of the interlayer connecting conductor can be reduced, so that the reaction can be suppressed and the formation of the intermetallic compound can be suppressed to be more than necessary. In particular, when the conductor portion contains ceramic particles that can fully suppress the reaction, in the manufactured laminated substrate, a part of the ceramic particles is in contact with both the intermetallic compound and the conductor portion.

[0050] In addition, in the laminated substrate of the present invention, the conductor portion may be an electrode or a through hole.

[0051] The multilayer substrate of the present invention can be used as a multilayer substrate with a built-in coil, and an ultra-small DCDC converter using the multilayer substrate can be widely used in electronic devices such as mobile information terminals and digital cameras.

[0052] Hereinafter, preferred embodiments of the multi-layer substrate of the present invention will be described with reference to the drawings.

[0053] [First embodiment]

[0054] First, a laminated substrate according to a first embodiment of the present invention will be described.

[0055] Figure 1A It is a cross-sectional view schematically showing an example of a multilayer substrate according to the first embodiment of the present invention.

[0056] Figure 1B yes Figure 1A An enlarged view of the dotted line portion.

[0057] Figure 1A The laminated substrate 1 shown includes a multilayer ceramic layer 2 in which a plurality of ceramic layers 10 are laminated, and a multilayer thermoplastic resin layer 3 in which a plurality of thermoplastic resin layers 20 are laminated.

[0058] exist Figure 1A In the laminated substrate 1 shown, a plurality of ceramic layers 2 are laminated on a plurality of thermoplastic resin layers 3 .

[0059] like Figure 1A and Figure 1B As shown, the multi-layer thermoplastic resin layer 3 includes a first thermoplastic resin layer 21 in contact with the multi-layer ceramic layer 2 .

[0060] like Figure 1B As shown, the first thermoplastic resin layer 21 includes a first main surface 21 a and a second main surface 21 b facing the first main surface 21 a , and has a via hole 21 h penetrating from the first main surface 21 a to the second main surface 21 b .

[0061] In addition, if Figure 1AAs shown, the first main surface 21 a of the first thermoplastic resin layer 21 is in contact with the multilayer ceramic layer 2 .

[0062] like Figure 1A As shown, the multilayer ceramic layer 2 includes a ceramic layer 11 arranged in contact with a first main surface 21a of a first thermoplastic resin layer 21. A first electrode 31 is formed on the main surface of the ceramic layer 11 in contact with the first main surface 21a. The first electrode 31 is a conductor portion in the laminate substrate of the present invention.

[0063] like Figure 1B As shown, the first electrode 31 includes ceramic particles 70 .

[0064] The multilayer thermoplastic resin layer 3 includes a second thermoplastic resin layer 22 disposed in contact with the second main surface 21 b .

[0065] A second electrode 32 is formed on a principal surface of the second thermoplastic resin layer 22 that is in contact with the second principal surface 21 b .

[0066] The interlayer connection conductor 50 connecting the first electrode 31 and the second electrode 32 is disposed in the via hole 21h. An intermetallic compound 61 is formed between the interlayer connection conductor 50 and the first electrode 31. An intermetallic compound 62 is formed between the interlayer connection conductor 50 and the second electrode 32.

[0067] The via hole 21 h has a tapered shape in which the opening on the first main surface 21 a side is larger than the opening on the second main surface 21 b side.

[0068] With such a shape, the connection strength between the interlayer connection conductor 50 and the first electrode 31 can be improved.

[0069] like Figure 1B As shown, in the laminated substrate 1 , ceramic particles 70 exist inside the intermetallic compound 61 .

[0070] Therefore, the difference between the linear expansion coefficient of the intermetallic compound 61 and the linear expansion coefficient of the first electrode 31 formed on the ceramic layer 11 can be reduced. As a result, the thermal stress applied to the intermetallic compound 61 can be reduced. Therefore, the intermetallic compound 61 can be prevented from being broken due to the thermal stress.

[0071] In the multilayer substrate 1 , a portion of the ceramic particles 70 exist as first ceramic particles 71 that are in contact with both the intermetallic compound 61 and the first electrode 31 .

[0072] When manufacturing the multilayer substrate 1 , the interlayer connection conductor 50 is connected to the first electrode 31 by liquid phase diffusion bonding. At this time, the intermetallic compound 61 is formed by the reaction of the first electrode 31 and the liquid phase component of the interlayer connection conductor 50 .

[0073] The presence of ceramic particles 70 inside the intermetallic compound 61 means that the first electrode 31 contains ceramic particles 70 when manufacturing the laminated substrate 1. If the first electrode 31 contains ceramic particles 70, the contact area between the first electrode 31 and the liquid phase component of the interlayer connection conductor can be reduced, so that the reaction can be suppressed and the formation of the intermetallic compound 61 can be suppressed beyond necessity. In particular, when the first electrode 31 contains ceramic particles 70 that can sufficiently suppress the reaction, in the manufactured laminated substrate 1, a part of the ceramic particles 70 is in contact with both the intermetallic compound 61 and the first electrode 31.

[0074] It should be explained, such as Figure 1A As shown, electrode patterns 2 a , through holes 2 b , etc. may be formed on the multilayer ceramic layer 2 , and electrode patterns 3 a , through holes 3 b , etc. may be formed on the multilayer thermoplastic resin layer 3 .

[0075] Preferred embodiments of the respective configurations of the multilayer substrate 1 will be described below.

[0076] (Interlayer connection conductor)

[0077] The interlayer connection conductor 50 is formed by filling the conductive paste containing the first metal powder and the second metal powder having a higher melting point than the first metal powder into the via hole 21h, and then melting the conductive paste and solidifying it. At this time, the first metal powder contained in the conductive paste reacts with the first electrode 31 to form an intermetallic compound 61.

[0078] Preferably, the first metal powder is composed of Sn or a Sn alloy, and the second metal powder is composed of a Cu—Ni alloy or a Cu—Mn alloy.

[0079] In addition, the conductive paste is described in detail in the <Method for Producing a Laminated Substrate> described later.

[0080] (Multilayer ceramic layer)

[0081] The multilayer ceramic layer 2 is composed of a ceramic layer 10 including a ceramic layer 11 .

[0082] As a material constituting the ceramic layer 10, for example, a low temperature co-fired ceramic (LTCC) material can be cited. A low temperature co-fired ceramic material refers to a ceramic material that can be sintered at a temperature below 1000°C and can be co-fired with Au, Ag, Cu, etc., which have a low resistivity. As a low temperature co-fired ceramic material, specifically, a glass composite low temperature co-fired ceramic material formed by mixing borosilicate glass with ceramic powders such as alumina, zirconia, magnesia, and forsterite, a microcrystalline glass-based low temperature co-fired ceramic material using microcrystalline glass of ZnO-MgO-Al2O3-SiO2, and a non-glass-based low temperature co-fired ceramic material using BaO-Al2O3-SiO2 ceramic powder, Al2O3-CaO-SiO2-MgO-B2O3 ceramic powder, etc. can be cited.

[0083] The thickness of the ceramic layer 10 is preferably appropriately determined according to the design, and is preferably 5 μm to 100 μm, for example.

[0084] The first electrode 31 , the electrode pattern 2 a , and the through hole 2 b are preferably a sintered body of a conductive paste composed of a conductive powder, a plasticizer, and a binder.

[0085] The first electrode 31, the electrode pattern 2a, and the through hole 2b are preferably a sintered body of copper (Cu) or an alloy thereof.

[0086] It should be noted that the first electrode 31 , the electrode pattern 2 a , and the through hole 2 b may contain silver (Ag), aluminum (Al), nickel (Ni), stainless steel (SUS), gold (Au), and alloys thereof.

[0087] In addition, the first electrode 31 , the electrode pattern 2 a , and the through hole 2 b may be made of the same material or different materials.

[0088] The thickness of the first electrode 31 is preferably appropriately determined according to the design, and is preferably 5 μm to 20 μm, for example. In this specification, “the thickness of the first electrode” refers to the maximum thickness of the first electrode.

[0089] (Ceramic particles)

[0090] The ceramic particles 70 may be particles formed by calcining a glass component and a ceramic material or a ceramic component obtained by pre-calcining both of them.

[0091] As the glass component, borosilicate glass, ZnO-MgO-Al2O3-SiO2-based microcrystalline glass, or the like can be used.

[0092] In addition, the ceramic particles 70 may contain 50 mass % or more of a glass component.

[0093] Examples of the ceramic material include alumina, zirconia, titania, quartz, barium titanate, silicon carbide, zinc oxide, forsterite, etc. Among them, alumina is preferred.

[0094] In addition, the ceramic particles 70 may contain 50 mass % or more of aluminum oxide.

[0095] The material of the ceramic particles 70 may be the same material as that constituting the ceramic layer 11 .

[0096] The average particle size of the ceramic particles 70 is preferably 0.5 μm to 3 μm.

[0097] In the cross section of the intermetallic compound 61 in the direction perpendicular to the first main surface 21 a of the laminated substrate 1 , the ratio of the area occupied by the ceramic particles 70 is preferably 0.1% to 20.0%, and more preferably 1.0% to 10.0%.

[0098] If the area ratio is less than 0.1%, the ratio of the ceramic particles is small, and it is difficult to reduce the difference between the linear expansion coefficient of the intermetallic compound and the linear expansion coefficient of the first electrode.

[0099] If the ratio of the above area exceeds 20.0%, the ratio of the ceramic particles increases, the area in which the first electrode and the intermetallic compound are in contact becomes narrow, and the resistance value tends to increase.

[0100] In addition, the ratio of the above-mentioned area in the cross section of the intermetallic compound in the direction perpendicular to the first main surface is measured by the following method.

[0101] First, a cross section of the intermetallic compound in a direction perpendicular to the first main surface of the multilayer substrate is photographed using a scanning electron microscope (SEM).

[0102] In the captured image, a range of 20 μm in length×20 μm in width was arbitrarily selected, and the ratio of the area occupied by the ceramic particles in the range was calculated.

[0103] The above-mentioned calculation of the proportion of ceramic particles was performed at three locations.

[0104] The average value of the ratio of the ceramic particles in each portion is defined as the “ratio of the area occupied by the ceramic particles in the cross section of the intermetallic compound in the direction perpendicular to the first main surface”.

[0105] In the stacked substrate 1, in the cross section of the intermetallic compound in the direction perpendicular to the first main surface, when the line forming the interface between the intermetallic compound and the first electrode (conductor portion) is set as the first line, and the line forming the interface between the intermetallic compound and the first ceramic particle is set as the second line, the ratio of the total length of the second line to the total length of the first line and the second line is preferably 0.1% to 50.0%, and more preferably 1.0% to 20.0%.

[0106] If the ratio is less than 0.1%, the proportion of ceramic particles is small, and when the first electrode and the interlayer connection conductor are connected during the manufacture of the laminated substrate, it is difficult to reduce the contact area between the liquid phase components of the first electrode and the interlayer connection conductor, and intermetallic compounds are likely to be widely formed.

[0107] If the ratio exceeds 50.0%, the number of the first ceramic particles increases, the area in which the first electrode and the intermetallic compound are in contact becomes narrow, and the resistance value tends to increase.

[0108] In addition, the ratio of the total length of the second line to the total length of the first line and the second line is measured by the following method.

[0109] First, a cross section of the first electrode and the intermetallic compound in a direction perpendicular to the first main surface of the multilayer substrate is photographed using a scanning electron microscope (SEM).

[0110] Then, in the cross-sectional image, the interface between the intermetallic compound and the first electrode is defined as the first line, and the interface between the intermetallic compound and the first ceramic particle is defined as the second line. Then, the length of the first line and the length of the second line are calculated from the number of pixels of the first line and the number of pixels of the second line.

[0111] Then, the value obtained by dividing the total length of the second line by the total length of the first line and the second line is calculated.

[0112] Repeat the same operation three times on other sections.

[0113] Then, the average value of the calculated numerical values ​​is defined as “the ratio of the total length of the second line to the total length of the first line and the second line”.

[0114] (Multi-layer thermoplastic resin layer)

[0115] The multilayer thermoplastic resin layer 3 is composed of a thermoplastic resin layer 20 including a first thermoplastic resin layer 21 and a second thermoplastic resin layer 22 .

[0116] Examples of the material constituting the thermoplastic resin layer 20 include liquid crystal polymer (LCP), thermoplastic polyimide resin, polyetheretherketone resin (PEEK), polyphenylene sulfide resin (PPS), and the like.

[0117] Among them, liquid crystal polymer (LCP) is preferred. Liquid crystal polymer has a lower water absorption rate than other thermoplastic resins, and can prevent changes in electrical characteristics and reduction in electrical connection reliability.

[0118] The thickness of the thermoplastic resin layer 20 is preferably appropriately determined according to the design, and is preferably 10 μm to 100 μm, for example.

[0119] like Figure 1B As shown, the via hole 21h formed in the first thermoplastic resin layer 21 has a tapered shape.

[0120] In addition, the tapered shape preferably has a different inclination angle in stages. In this case, the inclination angle may be changed in two stages, or may be changed in three or more stages.

[0121] It should be noted that in the laminated substrate of the present invention, the conductive hole can be a tapered shape in which the opening on the first main surface side is smaller than the opening on the second main surface side, or can be a cylindrical shape in which the opening on the first main surface side and the opening on the second main surface side are the same size.

[0122] The diameter of the opening of the via hole 21 h on the first main surface 21 a side is preferably 20 μm to 200 μm.

[0123] The diameter of the opening of the via hole 21h on the second main surface 21b side is preferably 20 μm to 200 μm.

[0124] Examples of materials for the second electrode 32 and the electrode pattern 3a include copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), stainless steel (SUS), and alloys thereof. The second electrode 32 and the electrode pattern 3a can be formed by laminating a metal foil on the thermoplastic resin layer 20 and patterning it by etching or the like.

[0125] In addition, the second electrode 32 and the electrode pattern 3 a may be made of the same material or different materials.

[0126] In addition, a preferred material for the via 2 b is the same as a preferred material for the interlayer connection conductor 50 .

[0127] The thickness of the second electrode 32 is preferably appropriately determined according to the design, and is preferably 3 μm to 40 μm, for example.

[0128] Next, another example of the multilayer substrate according to the first embodiment of the present invention will be described.

[0129] Figure 2 This is a cross-sectional view schematically showing an example of the vicinity of the interlayer connection conductor in another example of the multilayer substrate according to the first embodiment of the present invention.

[0130] exist Figure 2 The illustrated multilayer substrate 101 has the same configuration as the above-described multilayer substrate 1 except that the intermetallic compound 61 is formed so as to intrude into a portion between the first ceramic particles 71 and the first electrode 31 .

[0131] When the intermetallic compound 61 is formed so as to infiltrate a portion between the first ceramic particles 71 and the first electrode 31 , the connection strength between the intermetallic compound 61 and the first electrode 31 can be increased by the anchor effect, thereby improving the connection reliability.

[0132] As a method for forming the intermetallic compound 61 so as to infiltrate a portion between the first ceramic particles 71 and the first electrode 31 , there is a method of adjusting the temperature and pressure when connecting the interlayer connection conductor 50 and the first electrode 31 during the manufacture of the laminated substrate 101 .

[0133] In addition, by adjusting the average particle size of the ceramic particles 70 and the composition of the interlayer connection conductor 50, it is also possible to form Figure 2 The structure shown.

[0134] Next, a method for producing a laminated substrate according to the first embodiment of the present invention will be described. In the following description, a case where the ceramic layer is composed of an LTCC material will be described.

[0135] <LTCC green sheet preparation process>

[0136] Figure 3 This is a process diagram schematically showing an example of an LTCC green sheet preparation process in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0137] When manufacturing the laminated substrate according to the first embodiment of the present invention, first, Figure 3 As shown, a plurality of LTCC green sheets 10 ′ are prepared.

[0138] The LTCC green sheet 10 ′ can be prepared by the following method.

[0139] First, ceramic powder, a binder, and a plasticizer are mixed in arbitrary amounts to prepare slurry. As the ceramic powder, the materials mentioned above as the preferred materials for the ceramic layer 10 can be used. As the binder and the plasticizer, conventionally known materials can be used.

[0140] Next, the slurry is applied onto a carrier film to form a sheet, thereby producing an LTCC green sheet 10 ′.

[0141] The slurry can be applied using a lip coater or a doctor blade. At this time, the thickness of the LTCC green sheet 10 ′ is preferably 5 μm to 100 μm.

[0142] <LTCC green sheet via hole filling process>

[0143] Figure 4A and Figure 4BThis is a process diagram schematically showing an example of a via hole filling step of an LTCC green sheet in the method for manufacturing a laminated substrate according to the first embodiment of the present invention.

[0144] Next, if Figure 4A As shown, a via hole 10h' is formed in the LTCC green sheet 10'. The method for forming the via hole 10h' is not particularly limited, and the via hole 10h' can be formed using a mechanical punch, a CO2 laser, a UV laser, or the like.

[0145] The opening diameter of the via hole 10h' is not particularly limited, but is preferably 20 μm to 200 μm.

[0146] Next, if Figure 4B As shown, conductive paste 2b' consisting of conductive powder, plasticizer, and binder is filled into via hole 10h'.

[0147] It should be noted that ceramic powder constituting the LTCC green sheet 10' may be added to the conductive paste 2b'. If the conductive paste 2b' contains such ceramic powder, the difference in shrinkage between the LTCC green sheet 10' and the conductive paste 2b' becomes small. As a result, it is possible to prevent cracks from being generated during the firing of the LTCC green sheet 10' and the conductive paste 2b'.

[0148] <LTCC green sheet electrode pattern formation process>

[0149] Figure 5 This is a process diagram schematically showing an example of an electrode pattern forming step of an LTCC green sheet in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0150] Next, if Figure 5 As shown, the electrode pattern 2a' is printed on the surface of the LTCC green sheet 10' using a conductive paste composed of conductive powder, a plasticizer, and a binder. As a printing method, screen printing, inkjet printing, gravure printing, etc. can be used.

[0151] It should be noted that in the subsequent process, a plurality of LTCC green sheets 10' are stacked to form a stack. In the stack, a portion of the electrode patterns 2a' of the LTCC green sheet 10' located on the outermost layer has an electrode pattern ( Figure 5 In the manufacturing process, the first electrode (indicated by reference numeral “ 31 ′”) becomes the first electrode connected to the interlayer connection conductor in the manufactured multilayer substrate.

[0152] The LTCC green sheet 10 ′ on which the electrode pattern 31 ′ is formed becomes a ceramic substrate in contact with the first main surface of the first thermoplastic resin layer in the manufactured laminated substrate.

[0153] In this step, unfired ceramic particles 70' are mixed with the conductive paste for forming the electrode pattern 31'. The unfired ceramic particles 70' are preferably composed of a glass composition and a ceramic material or a ceramic component obtained by pre-firing both.

[0154] The content of the unfired ceramic particles 70 ′ in the inorganic solid component contained in the conductive paste for forming the electrode pattern 31 ′ is preferably 0.1% by weight to 20% by weight.

[0155] If the content is less than 0.1 wt %, the content of ceramic particles formed in the subsequent steps becomes small, making it difficult to obtain the effect of reducing the linear expansion coefficient of the intermetallic compound and the effect of preventing the formation of the intermetallic compound.

[0156] <LTCC green sheet lamination process>

[0157] Figure 6 This is a process diagram schematically showing an example of a LTCC green sheet lamination step in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0158] Next, if Figure 6 As shown, a plurality of LTCC green sheets 10' are stacked to produce an LTCC green sheet stack 2'. The number of stacked sheets is preferably appropriately determined according to the design.

[0159] Thereafter, the LTCC green sheet stack 2' is placed in a mold and pressure-bonded. The pressure and temperature are preferably set arbitrarily according to the design.

[0160] <LTCC green sheet stacking process>

[0161] Figure 7 This is a process diagram schematically showing an example of a firing step of an LTCC green sheet laminate in the method for producing a laminate substrate according to the first embodiment of the present invention.

[0162] Next, if Figure 7 As shown, the multilayer ceramic layer 2 is formed by heating and firing the LTCC green sheet stack 2 ′.

[0163] By performing this process, conductive paste 2b' is fired to form through-hole 2b, and electrode pattern 2a' and electrode pattern 31' are fired to form electrode pattern 2a and first electrode 31. Unfired ceramic particles 70' become ceramic particles 70.

[0164] The calcination can be performed using a calcination furnace such as a batch furnace or a belt furnace. The calcination conditions are not particularly limited, but are preferably 800°C to 1000°C.

[0165] In addition, when conductive paste 2b', electrode pattern 2a', and electrode pattern 31' contain copper (Cu), it is preferable to perform calcination in a reducing atmosphere.

[0166] <Thermoplastic resin layer preparation process>

[0167] Figure 8 This is a process diagram schematically showing an example of a thermoplastic resin layer preparation step in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0168] Next, if Figure 8 As shown, a plurality of sheet-shaped thermoplastic resin layers 20 are prepared. Preferred materials for the thermoplastic resin layer 20 have been described above, and the description here is omitted.

[0169] The thickness of the thermoplastic resin layer 20 is preferably 10 μm to 100 μm.

[0170] <Step of forming an electrode pattern on the thermoplastic resin layer>

[0171] Fig. 9A and Fig. 9B This is a process diagram schematically showing an example of a step of forming an electrode pattern of a thermoplastic resin layer in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0172] Next, if Fig. 9A As shown in FIG. 1 , a metal foil 3a' is laminated on the main surface of the thermoplastic resin layer 20. Next, as shown in FIG. Fig. 9B As shown, the electrode pattern 3a is formed by patterning the metal foil 3a' by etching or the like.

[0173] Examples of the metal foil 3 a ′ include copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), stainless steel (SUS), and alloys thereof.

[0174] In addition, it is preferred that one main surface of the metal foil 3 a ′ is a glossy surface and the other main surface is a matte surface. It is preferred that the metal foil 3 a ′ is laminated so that the matte surface is in contact with the main surface of the thermoplastic resin layer 20 .

[0175] The matte surface of the metal foil 3a' is subjected to a roughening treatment, and the surface roughness Rz (JIS B0601-2001) is preferably 1 μm to 15 μm.

[0176] It should be noted that in the subsequent process, a plurality of thermoplastic resin layers 20 are stacked to form a laminate. In the laminate, the outermost thermoplastic resin layer 20 becomes the first thermoplastic resin layer 21. In addition, the thermoplastic resin layer 20 in contact with the second main surface 21b of the first thermoplastic resin layer 21 becomes the second thermoplastic resin layer 22.

[0177] Furthermore, a portion of the electrode patterns 2 a formed on the principal surface of the second thermoplastic resin layer 22 on the second principal surface 21 b side serves as the second electrode 32 connected to the interlayer connection conductor in the manufactured laminated substrate.

[0178] <Step of filling via holes in thermoplastic resin layer>

[0179] Fig. 10A and Fig. 10B This is a process diagram schematically showing an example of a via hole filling step of a thermoplastic resin layer in the method for manufacturing a laminated substrate according to the first embodiment of the present invention.

[0180] Next, if Fig. 10A As shown, a via hole 21h, a via hole 22h, and a via hole 20h are formed in the first thermoplastic resin layer 21, the second thermoplastic resin layer 22, and the other thermoplastic resin layer 20, respectively.

[0181] The method for forming these via holes is not particularly limited, and they can be formed using a mechanical punch, a CO 2 laser, a UV laser, or the like.

[0182] After forming these via holes, desmear treatment such as oxygen plasma treatment, corona discharge treatment, potassium permanganate treatment, etc. is preferably performed.

[0183] The opening diameters of the via hole 21h, the via hole 22h, and the via hole 20h are not particularly limited, but are preferably 20 μm to 200 μm.

[0184] It should be noted that Fig. 10A In order to facilitate the display of the internal structure in a plane, a via hole is formed directly below the electrode pattern 3a. There are places where the via hole does not appear to be formed as a through hole, but in fact, the formation position of the electrode pattern 3a and the formation position of the via hole are offset in the depth direction, and the via hole is formed as a through hole.

[0185] Next, if Fig. 10B As shown, conductive paste 50 ′, which is a precursor of an interlayer connection conductor, is filled in via hole 21 h , via hole 22 h , and via hole 20 h .

[0186] The filling method is not particularly limited, and screen printing, vacuum printing, etc. can be used.

[0187] Conductive paste 50 ′ contains a first metal powder and a second metal powder having a higher melting point than the first metal powder.

[0188] It is preferred that the first metal powder contained in the conductive paste 50' is composed of Sn or a Sn alloy, and the second metal powder is composed of a Cu-Ni alloy or a Cu-Mn alloy. As such a conductive paste 50', for example, a conductive paste described in Japanese Patent No. 5146627 can be used. Hereinafter, the metal component contained in the first metal powder is also referred to as the first metal, and the metal component contained in the second metal powder is also referred to as the second metal.

[0189] Examples of Sn or Sn alloys include Sn alone or an alloy containing Sn and at least one selected from Cu, Ni, Ag, Au, Sb, Zn, Bi, In, Ge, Al, Co, Mn, Fe, Cr, Mg, Mn, Pd, Si, Sr, Te, and P. The Sn alloy preferably contains 70% by weight or more of Sn, more preferably 85% by weight or more of Sn.

[0190] The ratio of Ni in the Cu-Ni alloy is preferably 10 wt% to 15 wt%. In addition, the ratio of Mn in the Cu-Mn alloy is preferably 10 wt% to 15 wt%. Thus, sufficient Ni or Mn can be supplied to produce the desired intermetallic compound. When the ratio of Ni in the Cu-Ni alloy and the ratio of Mn in the Cu-Mn alloy are less than 10 wt%, Sn will not all become intermetallic compounds and will easily remain. In addition, when the ratio of Ni in the Cu-Ni alloy and the ratio of Mn in the Cu-Mn alloy exceed 15 wt%, Sn will not all become intermetallic compounds and will easily remain.

[0191] In addition, the Cu-Ni alloy or the Cu-Mn alloy may contain Mn and Ni at the same time, and may also contain a third component such as P.

[0192] The arithmetic mean particle size of the first metal powder and the second metal powder is preferably 3 μm to 10 μm, respectively. If the average particle size of these metal powders is too small, the manufacturing cost becomes high. In addition, the oxidation of the metal powder proceeds, which easily hinders the reaction. On the other hand, if the average particle size of these metal powders is too large, it is difficult to fill the conductive paste 50' into each via.

[0193] The ratio of the second metal in the conductive paste 50' to the metal component is preferably 30% by weight or more. That is, the ratio of the first metal in the conductive paste 50' to the metal component is preferably 70% by weight or less. In this case, the residual ratio of the first metal such as Sn can be further reduced, and the ratio of the intermetallic compound can be increased.

[0194] The ratio of the metal component in conductive paste 50' is preferably 70 wt% to 95 wt%. If the metal component exceeds 95 wt%, it is difficult to obtain conductive paste 50' with low viscosity and excellent filling properties. On the other hand, if the metal component is less than 70 wt%, the flux component is likely to remain.

[0195] Conductive paste 50' preferably contains a flux component. As the flux component, various known flux components used in materials of common conductive pastes can be used, including resins. As components other than the resin, for example, carriers, solvents, thixotropic agents, activators, etc. can be cited.

[0196] The above-mentioned resin preferably includes at least one thermosetting resin selected from epoxy resin, phenolic resin, polyimide resin, silicone resin or its modified resin and acrylic resin, or at least one thermoplastic resin selected from polyamide resin, polystyrene resin, polymethacrylic resin, polycarbonate resin and cellulose resin.

[0197] As the above-mentioned carrier, for example, rosin-based resins composed of rosin and modified rosin derivatives thereof, synthetic resins, or mixtures thereof can be cited. As rosin-based resins composed of the above-mentioned rosin and modified rosin derivatives thereof, for example, gum rosin, tall rosin, wood rosin, polymerized rosin, hydrogenated rosin, formylated rosin, rosin ester, rosin-modified maleic acid resin, rosin-modified phenolic resin, rosin-modified alkyd resin and other various rosin derivatives can be cited. As synthetic resins composed of the above-mentioned rosin and modified rosin derivatives thereof, for example, polyester resins, polyamide resins, phenoxy resins, terpene resins, etc. can be cited.

[0198] As the above-mentioned solvent, alcohols, ketones, esters, ethers, aromatics, hydrocarbons, etc. are known, and specific examples thereof include benzyl alcohol, ethanol, isopropanol, butanol, diethylene glycol, ethylene glycol, glycerol, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, butyl benzoate, diethyl adipate, dodecane, tetradecene, α-terpineol, terpineol, 2-methyl-2,4-pentanediol, 2-ethylhexanediol, toluene, xylene, propylene glycol monophenyl ether, diethylene glycol monohexyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diisobutyl adipate, hexanediol, cyclohexanedimethanol, 2-pinyloxyethanol, 2-dihydropinyloxyethanol, and mixtures thereof. Preferred are terpineol, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0199] Specific examples of the thixotropic agent include hydrogenated castor oil, carnauba wax, amides, hydroxy fatty acids, dibenzylidene sorbitol, bis(p-methylbenzylidene) sorbitol, beeswax, stearamide, ethylenebishydroxystearic acid amide, etc. In addition, as necessary, a substance to which fatty acids such as caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, hydroxystearic acid such as 1,2-hydroxystearic acid, an antioxidant, a surfactant, an amine, etc. are added can also be used as a thixotropic agent.

[0200] Examples of the activator include amine hydrohalides, organic halides, organic acids, organic amines, and polyols.

[0201] Examples of the hydrohalide salts of the amines include diphenylguanidine hydrobromide, diphenylguanidine hydrochloride, cyclohexylamine hydrobromide, ethylamine hydrochloride, ethylamine hydrobromide, diethylaniline hydrobromide, diethylaniline hydrobromide, triethanolamine hydrobromide, and monoethanolamine hydrobromide.

[0202] Examples of the organic halide include chlorinated paraffin, tetrabromoethane, dibromopropanol, 2,3-dibromo-1,4-butanediol, 2,3-dibromo-2-butene-1,4-diol, and tris(2,3-dibromopropyl)isocyanurate.

[0203] Examples of the organic acid include malonic acid, fumaric acid, glycolic acid, citric acid, malic acid, succinic acid, phenylsuccinic acid, maleic acid, salicylic acid, anthranilic acid, glutaric acid, suberic acid, adipic acid, sebacic acid, stearic acid, abietic acid, benzoic acid, trimellitic acid, pyromellitic acid, and dodecanoic acid.

[0204] Examples of the organic amine include monoethanolamine, diethanolamine, triethanolamine, tributylamine, aniline, and diethylaniline.

[0205] Examples of the polyol include erythritol, pyrogallol, and ribitol.

[0206] <Thermoplastic resin layer lamination step>

[0207] Fig.11 This is a process diagram schematically showing an example of a lamination step of a thermoplastic resin layer in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0208] Next, if Fig.11 As shown, the first thermoplastic resin layer 21 , the second thermoplastic resin layer 22 , and the other thermoplastic resin layer 20 are stacked to form a multilayer thermoplastic resin layer 3 .

[0209] <Step of laminating multiple ceramic layers and multiple thermoplastic resin layers>

[0210] Fig. 12A and Fig. 12B This is a process diagram schematically showing an example of a lamination step of a plurality of ceramic layers and a plurality of thermoplastic resin layers in the method for producing a laminated substrate according to the first embodiment of the present invention.

[0211] Next, if Fig. 12A As shown, multilayer ceramic layers 2 are stacked on multilayer thermoplastic resin layers 3. At this time, conductive paste 50' filled in first thermoplastic resin layer 21 of multilayer thermoplastic resin layer 3 is aligned so as to contact the exposed surface of first electrode 31 of ceramic layer 11 disposed on the outermost layer of multilayer ceramic layer 2.

[0212] Afterwards, if Fig. 12B As shown, the multi-layer thermoplastic resin layer 3 and the multi-layer ceramic layer 2 are integrated by applying pressure and heat.

[0213] At this time, the first thermoplastic resin layer 21 follows the surface irregularities of the ceramic layer 11 , and the multi-layered thermoplastic resin layer 3 and the multi-layered ceramic layer 2 are closely attached to each other by the anchor effect.

[0214] In this step, for example, there can be mentioned a method of treating at 230° C. to 350° C. under a normal pressure.

[0215] In this process, the conductive paste 50 ′ is melted and then solidified to form the interlayer connection conductor 50 .

[0216] The interlayer connection conductor 50 and the first electrode 31 are connected by liquid phase diffusion bonding. At this time, an intermetallic compound 61 is formed between the interlayer connection conductor 50 and the first electrode 31 .

[0217] This liquid phase diffusion bonding will be described using the drawings.

[0218] FIG. 13A to FIG. 13D This is an explanatory diagram schematically showing an example of connecting an interlayer connection conductor and a first electrode by liquid phase diffusion bonding.

[0219] like Fig.13A As shown, conductive paste 50 ′ includes first metal powder 51 and second metal powder 52 having a higher melting point than first metal powder 51 . Conductive paste 50 ′ is in contact with first electrode 31 .

[0220] like Fig. 13B As shown, when the conductive paste 50 ′ is heated in this state and the melting point of the first metal powder 51 is reached, the first metal powder 51 is melted to become the first metal 51 a in the liquid phase.

[0221] Then, if the heating is continued further, Fig. 13CAs shown, the first metal 51 a in the liquid phase reacts with the second metal powder 52 to form an intermetallic compound 60 .

[0222] Furthermore, the first metal 51 a in the liquid phase spreads so as to diffuse toward the first electrode 31 , and the first metal 51 a in the liquid phase reacts with the metal constituting the first electrode 31 to form an intermetallic compound 61 .

[0223] The first electrode 31 includes ceramic particles 70. The ceramic particles 70 suppress the diffusion of the first metal 51a in the liquid phase. Therefore, it is possible to prevent the intermetallic compound 61 from being formed over a wide range.

[0224] Afterwards, if the heating is terminated and the temperature drops, Fig.13D As shown, the first metal 51a in the liquid phase solidifies to become the interlayer connection conductor 50. At this time, among the ceramic particles 70, there are particles that become the first ceramic particles 71 that are in contact with both the first electrode 31 and the intermetallic compound 61.

[0225] It should be noted that Fig.13D In FIG. 1 , for the sake of convenience, the outline of the intermetallic compound 60 derived from the second metal powder 52 is indicated by a dotted line. However, in reality, the boundary is not clear and the intermetallic compound 60 does not appear to be in a particle shape.

[0226] In this process, the interlayer connection conductor 50 and the second electrode 32 are also connected by liquid phase diffusion bonding, so the intermetallic compound 61 is also formed between the interlayer connection conductor 50 and the second electrode 32 .

[0227] The multilayer substrate 1 can be manufactured through the above steps.

[0228] [Second embodiment]

[0229] Next, a multilayer substrate according to a second embodiment of the present invention will be described.

[0230] Fig.14 This is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a laminate substrate according to a second embodiment of the present invention.

[0231] exist Fig.14 The illustrated multilayer substrate 201 has the same configuration as the multilayer substrate 1 according to the first embodiment except for the following points.

[0232] In the multilayer substrate 201 , the first electrode 231 includes a first conductor layer 231 a on the first thermoplastic resin layer 21 side and a second conductor layer 231 b stacked on the first conductor layer 231 a .

[0233] Furthermore, the weight ratio of the ceramic particles 70 included in the first conductive layer 231 a is lower than the weight ratio of the ceramic particles 70 included in the second conductive layer 231 b . It should be noted that the first conductive layer 231 a may not contain the ceramic particles 70 .

[0234] It should be noted that when the first conductor layer 231a contains ceramic particles 70, the ratio of the weight of the ceramic particles 70 contained in the first conductor layer 231a to the weight of the ceramic particles 70 contained in the second conductor layer 231b, that is, [the weight of the ceramic particles contained in the first conductor layer] / [the weight of the ceramic particles contained in the second conductor layer] is preferably greater than 0 and less than 0.7.

[0235] In the laminated substrate 201, the thickness of the first conductor layer 231a is preferably 5 μm to 10 μm. In addition, the thickness of the second conductor layer 231b is preferably 5 μm to 10 μm.

[0236] The laminated substrate 201 having such a structure can be produced by the same method as the method for producing the laminated substrate according to the first embodiment of the present invention, except that the above-mentioned <LTCC green sheet laminated body firing step> is changed as follows.

[0237] That is, in the above-mentioned <LTCC green sheet stack firing step>, when forming the first electrode 231, a conductive paste containing a large amount of unfired ceramic particles is printed, and a conductive paste containing a small amount of unfired ceramic particles or no unfired ceramic particles is printed thereon.

[0238] The conductive paste containing a large amount of unfired ceramic particles preferably contains 5 to 70 volume % of the inorganic solid content of the same ceramic calcined powder as that of the LTCC green sheet.

[0239] The conductive paste containing a small amount of unfired ceramic particles preferably contains 2% by volume or more of the same ceramic calcined powder as the LTCC green sheet and / or alumina in terms of the inorganic solid content.

[0240] When the multilayer substrate 201 is manufactured by such a method, when the interlayer connection conductor 50 and the first electrode 231 are connected by liquid phase diffusion bonding, the intermetallic compound 261 is formed as follows.

[0241] When the interlayer connection conductor 50 and the first electrode 231 are connected by liquid phase diffusion bonding, the first conductor layer 231 a quickly turns into the intermetallic compound 261 because the weight ratio of the ceramic particles 70 contained in the first conductor layer 231 a is low.

[0242] When the intermetallic compound 261 reaches the second conductor layer 231 b , the second conductor layer 231 b is unlikely to become the intermetallic compound 261 because the weight ratio of the ceramic particles 70 included in the second conductor layer 231 b is high.

[0243] That is, the intermetallic compound 261 is difficult to be formed at the boundary between the first conductive layer 231 a and the second conductive layer 231 b .

[0244] Therefore, by adjusting the weight ratio of the ceramic particles 70 contained in the first conductor layer 231 a and the second conductor layer 231 b , the thickness of the first conductor layer 231 a and the second conductor layer 231 b , etc., the range in which the intermetallic compound 261 is formed can be controlled.

[0245] For such reasons, it is possible to prevent the intermetallic compound 261 from excessively diffusing in the thickness direction.

[0246] Furthermore, since the first conductor layer 231 a easily turns into the intermetallic compound 261 , the interlayer connection conductor 50 and the first electrode 231 can be reliably connected.

[0247] [Third Embodiment]

[0248] Next, a multilayer substrate according to a third embodiment of the present invention will be described.

[0249] Fig.15 This is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a multilayer substrate according to a third embodiment of the present invention.

[0250] exist Fig.15 The illustrated multilayer substrate 301 has the same configuration as the multilayer substrate 1 according to the first embodiment except for the following points.

[0251] In the laminated substrate 301 , the first electrode 31 is not formed, a through hole 302 b connected to the interlayer connection conductor 50 is formed in the ceramic layer 11 , and an intermetallic compound 361 is formed between the interlayer connection conductor 50 and the through hole 302 b .

[0252] Ceramic particles 70 exist inside the intermetallic compound 361 , and a portion of the ceramic particles 70 are first ceramic particles 71 that are in contact with both the intermetallic compound 361 and the through hole 302 b .

[0253] In the multilayer substrate 301 , the through hole 302 b functions as a conductor portion.

[0254] In the laminated substrate 301 having such a structure, since the intermetallic compound 361 contains ceramic particles, the difference between the linear expansion coefficient of the intermetallic compound 361 and the linear expansion coefficient of the through hole 302b can be reduced. As a result, the thermal stress applied to the intermetallic compound 361 can be reduced. Therefore, the intermetallic compound 361 can be prevented from being broken due to the thermal stress.

[0255] A preferred material for the through hole 302 b is the same as the preferred material for the first electrode 31 described above.

[0256] It is particularly preferable that the through hole 302b is a sintered body of copper (Cu) or an alloy thereof.

[0257] [Fourth embodiment]

[0258] Next, a multilayer substrate according to a fourth embodiment of the present invention will be described.

[0259] Fig.16 This is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a laminate substrate according to a fourth embodiment of the present invention.

[0260] exist Fig.16 The illustrated multilayer substrate 401 has the same configuration as the multilayer substrate 301 according to the third embodiment except for the following points.

[0261] In the multilayer substrate 401 , the through hole 402 b includes a first conductor layer 402 b 1 on the first thermoplastic resin layer 21 side and a second conductor layer 402 b 2 stacked on the first conductor layer 402 b 1 .

[0262] Furthermore, the weight ratio of the ceramic particles 70 contained in the first conductive layer 402b1 is lower than the weight ratio of the ceramic particles 70 contained in the second conductive layer 402b2. It should be noted that the first conductive layer 402b1 may not contain the ceramic particles 70.

[0263] It should be noted that when the first conductor layer 402b1 contains ceramic particles 70, the ratio of the weight of the ceramic particles 70 contained in the first conductor layer 402b1 to the weight of the ceramic particles 70 contained in the second conductor layer 402b2, i.e., [the weight of the ceramic particles contained in the first conductor layer] / [the weight of the ceramic particles contained in the second conductor layer] is preferably greater than 0 and less than 0.7.

[0264] When the interlayer connection conductor 50 and the via 402 b are connected by liquid phase diffusion bonding, the first conductor layer 402 b 1 quickly turns into the intermetallic compound 461 because the weight ratio of the ceramic particles 70 contained in the first conductor layer 402 b 1 is low.

[0265] When the intermetallic compound 461 reaches the second conductor layer 402 b 2 , the second conductor layer 402 b 2 is unlikely to become the intermetallic compound 461 because the weight ratio of the ceramic particles 70 included in the second conductor layer 402 b 2 is high.

[0266] That is, the intermetallic compound 461 is difficult to be formed at the boundary between the first conductive layer 402 b 1 and the second conductive layer 402 b 2 .

[0267] It should be noted that Fig.16 In the embodiment, the first conductor layer 402b1 remains, but in the multilayer substrate of the present invention, the first conductor layer may be entirely converted into an intermetallic compound.

[0268] For such reasons, it is possible to prevent the intermetallic compound 461 from excessively diffusing in the thickness direction.

[0269] Furthermore, since the first conductor layer 402 b 1 easily becomes the intermetallic compound 461 , the interlayer connection conductor 50 and the via 402 b can be reliably connected.

[0270] A preferred material for the first conductor layer 402 b 1 is the same as the preferred material for the first conductor layer 231 a described above.

[0271] A preferred material for the second conductor layer 402b2 is the same as the preferred material for the second conductor layer 231b described above.

[0272] [Implementation Method No. 5]

[0273] Next, a multilayer substrate according to a fifth embodiment of the present invention will be described.

[0274] Fig.17 It is a cross-sectional view schematically showing an example of the vicinity of an interlayer connection conductor of a laminate substrate according to a fifth embodiment of the present invention.

[0275] Fig.17 The illustrated multilayer substrate 501 has the same configuration as the multilayer substrate 1 according to the first embodiment except for the following points.

[0276] In the laminated substrate 501 , a through hole 502 b is formed in the ceramic layer 11 so as to be connected to the first electrode 531 . The first electrode 531 and the through hole 502 b contain ceramic particles 70 .

[0277] Furthermore, in the laminate substrate 501 , the weight ratio of the ceramic particles 70 included in the first electrode 531 is lower than the weight ratio of the ceramic particles 70 included in the through hole 502 b . It should be noted that the first electrode 531 may not contain the ceramic particles 70 .

[0278] It should be noted that when the first electrode 531 includes ceramic particles 70, the ratio of the weight of the ceramic particles 70 included in the first electrode 531 to the weight of the ceramic particles 70 included in the through hole 502b, that is, [the weight of the ceramic particles included in the first electrode] / [the weight of the ceramic particles included in the through hole] is preferably greater than 0 and less than 0.7.

[0279] A preferred material for the first electrode 531 is the same as the preferred material for the first conductive layer 231 a described above.

[0280] A preferred material for the through hole 502b is the same as the preferred material for the second conductor layer 231b described above.

[0281] In the multilayer substrate 501, both the first electrode 531 and the through hole 502b function as a conductive portion. In addition, the first electrode 531 functions as a first conductor layer, and the through hole 502b functions as a second conductor layer.

[0282] When the interlayer connection conductor 50 and the first electrode 531 are connected by liquid phase diffusion bonding, the first electrode 531 quickly turns into the intermetallic compound 561 because the weight ratio of the ceramic particles 70 contained in the first electrode 531 is low.

[0283] When the intermetallic compound 61 reaches the through hole 502 b , the through hole 502 b is unlikely to become the intermetallic compound 561 because the weight ratio of the ceramic particles 70 included in the second conductive layer 502 b 2 is high.

[0284] That is, the intermetallic compound 561 is difficult to be formed at the boundary between the first electrode 531 and the through hole 502 b .

[0285] For such reasons, it is possible to prevent the intermetallic compound 561 from excessively diffusing in the thickness direction.

[0286] In addition, since the first electrode 531 easily becomes the intermetallic compound 561 , the interlayer connection conductor 50 and the first electrode 531 can be reliably connected.

[0287] The following matters are described in this manual.

[0288] The present disclosure (1) relates to a laminated substrate comprising a first thermoplastic resin layer and a ceramic layer, wherein the first thermoplastic resin layer comprises a first main surface and a second main surface opposite to the first main surface, and has a via hole penetrating from the first main surface to the second main surface, the ceramic layer is arranged in contact with the first main surface, an interlayer connection conductor is arranged in the via hole, a conductor portion connected to the interlayer connection conductor is formed in the ceramic layer, an intermetallic compound is formed between the interlayer connection conductor and the conductor portion, ceramic particles exist inside the intermetallic compound, and a portion of the ceramic particles are first ceramic particles in contact with both the intermetallic compound and the conductor portion.

[0289] The present disclosure (2) is the laminated substrate according to the present disclosure (1), wherein the intermetallic compound is formed so as to intrude into a portion between the first ceramic particles and the conductor portion.

[0290] The present disclosure (3) is a laminate substrate according to the present disclosure (1) or (2), wherein a ratio of an area occupied by the ceramic particles in a cross section of the intermetallic compound in a direction perpendicular to the first main surface is 0.1% to 20.0%.

[0291] The present disclosure (4) is based on a laminated substrate described in any one of the present disclosures (1) to (3), wherein, in a cross section of the intermetallic compound in a direction perpendicular to the first main surface, when a line forming an interface between the intermetallic compound and the conductor portion is set as a first line and a line forming an interface between the intermetallic compound and the first ceramic particle is set as a second line, a ratio of a total length of the second line to a total length of the first line and the second line is 0.1% to 50.0%.

[0292] The present disclosure (5) is a laminated substrate based on any one of the present disclosures (1) to (4), wherein the conductor portion contains the ceramic particles, the conductor portion contains a first conductor layer on the first thermoplastic resin layer side and a second conductor layer laminated on the first conductor layer, and the weight ratio of the ceramic particles contained in the first conductor layer is lower than the weight ratio of the ceramic particles contained in the second conductor layer.

[0293] The present disclosure (6) is a laminate substrate according to any one of the present disclosures (1) to (5), wherein the conductor portion is an electrode.

[0294] The present disclosure (7) is a laminated substrate according to any one of the present disclosures (1) to (5), wherein the conductor portion is a through hole.

[0295] The present disclosure (8) is a laminate substrate according to any one of the present disclosures (1) to (7), wherein the ceramic particles contain 50% by weight or more of a glass component.

[0296] The present disclosure (9) is a laminate substrate according to any one of the present disclosures (1) to (7), wherein the ceramic particles contain 50% by mass or more of aluminum oxide.

[0297] The present disclosure (10) is a laminated substrate according to any one of the present disclosures (1) to (9), wherein the ceramic particles are made of the same material as that of the ceramic layer.

[0298] Explanation of symbols

[0299] 1, 101, 201, 301, 401, 501 laminated substrate

[0300] 2 multi-layer ceramic layer

[0301] 2'LTCC green sheet stack

[0302] 2a, 2a', 3a electrode patterns

[0303] 2b, 3b, 302b, 402b, 502b through holes

[0304] 3 multi-layer thermoplastic resin layer

[0305] 3a' Metal foil

[0306] 10.11 Ceramic layer

[0307] 10'LTCC Green Sheet

[0308] 10h', 20h, 21h, 22h vias

[0309] 20 Thermoplastic resin layer

[0310] 21 first thermoplastic resin layer

[0311] 21a First main surface of the first thermoplastic resin layer

[0312] 21b Second main surface of the first thermoplastic resin layer

[0313] 22 second thermoplastic resin layer

[0314] 31, 231, 531 1st electrode

[0315] 31' Electrode pattern

[0316] 31c Outline of the first electrode

[0317] 32 2nd electrode

[0318] 50 interlayer connection conductors

[0319] 50' Conductive paste

[0320] 51 No.1 Metal Powder

[0321] 51a The first metal in the liquid phase

[0322] 52 2nd Metal Powder

[0323] 60, 61, 62, 261, 361, 461, 561 intermetallic compounds

[0324] 70 Ceramic particles

[0325] 70' uncalcined ceramic particles

[0326] 71 No.1 Ceramic Particles

[0327] 231a, 402b1 1st conductor layer

[0328] 231b, 402b2 2nd conductor layer

Claims

1. A laminate substrate comprising a first thermoplastic resin layer and a ceramic layer, The first thermoplastic resin layer includes a first main surface and a second main surface opposite to the first main surface, and has a through hole penetrating from the first main surface to the second main surface. The ceramic layer is arranged in contact with the first main surface. An interlayer connection conductor is arranged in the via hole, A conductor portion connected to the interlayer connection conductor is formed on the ceramic layer. An intermetallic compound is formed between the interlayer connection conductor and the conductor portion, There are ceramic particles inside the intermetallic compound. Some of the ceramic particles are first ceramic particles in contact with both the intermetallic compound and the conductor portion.

2. The laminate substrate according to claim 1, wherein: The intermetallic compound is formed so as to intrude into a portion between the first ceramic particles and the conductor portion.

3. The laminated substrate according to claim 1 or 2, wherein: In a cross section of the intermetallic compound in a direction perpendicular to the first main surface, a ratio of an area occupied by the ceramic particles is 0.1% to 20.0%.

4. The laminated substrate according to any one of claims 1 to 3, wherein In the cross section of the intermetallic compound in a direction perpendicular to the first main surface, when the line forming the interface between the intermetallic compound and the conductor portion is set as the first line, and the line forming the interface between the intermetallic compound and the first ceramic particle is set as the second line, the ratio of the total length of the second line to the total length of the first line and the second line is 0.1% to 50.0%.

5. The laminated substrate according to any one of claims 1 to 4, wherein The conductor portion includes the ceramic particles, The conductor portion includes a first conductor layer on the first thermoplastic resin layer side and a second conductor layer stacked on the first conductor layer. The weight ratio of the ceramic particles contained in the first conductive layer is lower than the weight ratio of the ceramic particles contained in the second conductive layer.

6. The laminated substrate according to any one of claims 1 to 5, wherein The conductor part is an electrode.

7. The laminated substrate according to any one of claims 1 to 5, wherein The conductor portion is a through hole.

8. The laminated substrate according to any one of claims 1 to 7, wherein The ceramic particles contain 50 wt % or more of a glass component.

9. The laminated substrate according to any one of claims 1 to 7, wherein The ceramic particles contain 50 mass % or more of aluminum oxide.

10. The laminated substrate according to any one of claims 1 to 9, wherein The ceramic particles are made of the same material as that of the ceramic layer.

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